Hancock Whitney Corporation - 6 (HWC) 10-Q 7 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Nov. 01, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'HBHC	'
Entity Registrant Name	'HANCOCK HOLDING CO	'
Entity Central Index Key	'0000750577	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	81,568,836

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and due from banks	$332,359	$348,440
Interest-bearing bank deposits	467,218	267,236
Federal funds sold	4,340	1,604
Securities available for sale, at fair value (amortized cost of $1,640,299 and $1,408,780)	1,662,410	1,421,772
Securities held to maturity (fair value of $2,253,219 and $2,576,584)	2,250,960	2,611,352
Loans held for sale	15,098	24,515
Loans	13,348,574	12,324,817
Less: allowance for loan losses	-125,572	-133,626
Loans, net	13,223,002	12,191,191
Property and equipment, net of accumulated depreciation of $187,692 and $172,798	407,987	432,346
Prepaid expenses	66,996	65,220
Other real estate, net	55,898	76,668
Accrued interest receivable	44,164	42,977
Goodwill	621,193	625,675
Other intangible assets, net	139,256	159,773
Life insurance contracts	422,562	381,437
FDIC loss share receivable	81,906	113,834
Deferred tax asset, net	60,323	89,708
Other assets	130,278	155,503
Total assets	19,985,950	19,009,251
Deposits:	'	'
Noninterest-bearing demand	5,866,255	5,530,253
Interest-bearing transaction, savings, money market and time	9,870,439	9,830,263
Total deposits	15,736,694	15,360,516
Short-term borrowings	1,171,809	657,960
Long-term debt	376,452	385,826
Accrued interest payable	5,663	4,353
Other liabilities	185,990	175,527
Total liabilities	17,476,608	16,584,182
Stockholders' equity	'	'
Common stock- $3.33 par value per share; 350,000,000 shares authorized, 81,566,640 and 82,237,162 shares outstanding	271,617	273,850
Capital surplus	1,560,912	1,558,432
Retained earnings	703,506	628,166
Accumulated other comprehensive (loss), net	-26,693	-35,379
Total stockholders' equity	2,509,342	2,425,069
Total liabilities and stockholders' equity	$19,985,950	$19,009,251

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Securities available for sale, amortized cost	$1,640,299	$1,408,780
Held to maturity securities	2,253,219	2,576,584
Property and equipment, accumulated depreciation	$187,692	$172,798
Common stock, par value per share	$3.33	$3.33
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares outstanding	81,566,640	82,237,162

Consolidated_Statements_of_Inc

Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest income:	'	'	'	'
Loans, including fees	$150,481	$158,715	$453,066	$478,751
Loans held for sale	197	177	544	774
Securities-taxable	20,824	21,318	64,601	62,242
Securities-tax exempt	954	1,176	2,946	3,615
Federal funds sold and other short term investments	245	253	685	1,178
Total interest income	172,701	181,639	521,842	546,560
Interest expense:	'	'	'	'
Deposits	5,828	5,851	16,431	18,785
Short-term borrowings	238	1,074	2,109	3,448
Long-term debt and other interest expense	3,094	3,184	9,421	9,603
Total interest expense	9,160	10,109	27,961	31,836
Net interest income	163,541	171,530	493,881	514,724
Provision for loan losses	9,468	7,569	24,122	25,404
Net interest income after provision for loan losses	154,073	163,961	469,759	489,320
Noninterest income:	'	'	'	'
Service charges on deposit accounts	20,000	20,519	57,981	59,398
Trust fees	11,530	9,477	33,267	27,972
Bank card and ATM fees	11,641	12,221	33,806	34,678
Investment and annuity fees	5,506	5,186	15,555	14,955
Secondary mortgage market operations	2,313	2,467	6,036	10,989
Insurance commissions and fees	1,979	3,661	7,611	12,500
Amortization of FDIC loss share receivable	-2,760	-590	-9,989	-590
Other income	7,732	10,116	26,771	27,239
Total noninterest income	57,941	63,057	171,038	187,141
Noninterest expense:	'	'	'	'
Compensation expense	69,207	73,037	204,900	215,715
Employee benefits	11,957	16,340	38,812	49,184
Personnel expense	81,164	89,377	243,712	264,899
Net occupancy expense	10,848	12,369	32,983	37,099
Equipment expense	4,619	5,127	12,958	15,347
Data processing expense	13,004	12,031	38,310	36,346
Professional services expense	7,229	10,899	22,817	27,571
Amortization of intangibles	6,570	7,306	20,352	22,292
Telecommunications and postage	3,648	4,397	11,094	13,484
Deposit insurance and regulatory fees	2,967	3,789	8,677	11,635
Other real estate expense, net	-104	2,439	1,757	6,502
Other expense	19,134	34,471	60,259	68,882
Total noninterest expense	149,079	182,205	452,919	504,057
Income before income taxes	62,935	44,813	187,878	172,404
Income taxes	16,382	11,611	52,248	43,764
Net income	$46,553	$33,202	$135,630	$128,640
Basic earnings per common share	$0.56	$0.40	$1.62	$1.51
Diluted earnings per common share	$0.56	$0.40	$1.62	$1.51
Dividends paid per share	$0.24	$0.24	$0.72	$0.72
Weighted average shares outstanding-basic	81,721	82,091	81,965	83,404
Weighted average shares outstanding-diluted	81,942	82,205	82,204	83,496

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$46,553	$33,202	$135,630	$128,640
Other comprehensive income:	'	'	'	'
Net change in unrealized (losses) gains	-6,293	-9,685	9,119	-96,074
Reclassification adjustment for net (gains) losses realized and included in earnings	-6	1,553	2,195	5,835
Amortization of unrealized net gain (loss) on securities transferred to held to maturity	892	-1,456	2,463	-7,099
Other comprehensive (expense) income, before income taxes	-5,407	-9,588	13,777	-97,338
Income tax (benefit) expense	-2,005	-3,512	5,091	-35,492
Other comprehensive (loss) income net of income taxes	-3,402	-6,076	8,686	-61,846
Comprehensive income	$43,151	$27,126	$144,316	$66,794

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Stockholders Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]
In Thousands, except Share data
Balance, at Dec. 31, 2012	$2,453,278	$282,543	$1,647,638	$546,022	($22,925)
Balance, Shares at Dec. 31, 2012	'	84,847,796	'	'	'
Net income	128,640	'	'	128,640	'
Other comprehensive income	-61,846	'	'	'	-61,846
Comprehensive income	66,794	'	'	128,640	-61,846
Cash dividends declared ($0.72 per common share)	-61,000	'	'	-61,000	'
Common stock activity, long-term incentive plan	12,370	256	12,114	'	'
Common stock activity, long-term incentive plan, shares	'	76,801	'	'	'
Purchase of common stock	-115,000	-9,383	-105,617	'	'
Purchase of common stock, shares	'	-2,817,640	'	'	'
Balance at Sep. 30, 2013	2,356,442	273,416	1,554,135	613,662	-84,771
Balance, Shares at Sep. 30, 2013	'	82,106,957	'	'	'
Balance, at Dec. 31, 2013	2,425,069	273,850	1,558,432	628,166	-35,379
Balance, Shares at Dec. 31, 2013	'	82,237,162	'	'	'
Net income	135,630	'	'	135,630	'
Other comprehensive income	8,686	'	'	'	8,686
Comprehensive income	144,316	'	'	135,630	8,686
Cash dividends declared ($0.72 per common share)	-60,290	'	'	-60,290	'
Common stock activity, long-term incentive plan	10,214	749	9,465	'	'
Common stock activity, long-term incentive plan, shares	'	224,963	'	'	'
Purchase of common stock	-9,967	-2,982	-6,985	'	'
Purchase of common stock, shares	'	-895,485	'	'	'
Balance at Sep. 30, 2014	$2,509,342	$271,617	$1,560,912	$703,506	($26,693)
Balance, Shares at Sep. 30, 2014	'	81,566,640	'	'	'

Consolidated_Statements_of_Cha1

Consolidated Statements of Changes in Stockholders Equity (Unaudited) (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash dividends declared, per common share	$0.72	$0.72
Retained Earnings [Member]	'	'
Cash dividends declared, per common share	$0.72	$0.72

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$135,630	$128,640
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	22,976	24,178
Provision for loan losses	24,122	25,404
(Gain) loss on other real estate owned	-34	3,519
Deferred tax expense	24,295	20,807
Increase in cash surrender value of life insurance contracts	-6,960	-8,764
Gain on disposal of other assets	-1,411	'
Write-downs on closed branch transfers to other real estate owned	2,683	8,450
Net decrease in loans originated for sale	7,017	35,497
Net amortization of securities premium/discount	12,891	27,095
Amortization of intangible assets	20,352	22,292
Amortization of FDIC indemnification asset	9,989	590
Stock-based compensation expense	10,514	10,435
(Decrease) increase in interest payable and other liabilities	-9,132	7,673
Net payments (to) from FDIC	-366	60,886
Decrease (increase) in FDIC loss share receivable	7,729	-7,108
Decrease in other assets	21,086	43,091
Other, net	6,256	8,502
Net cash provided by operating activities	287,637	411,187
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Proceeds from sales of securities available for sale	1,301	'
Proceeds from maturities of securities available for sale	218,351	510,886
Purchases of securities available for sale	-440,187	-1,017,578
Proceeds from maturities of securities held to maturity	358,649	419,334
Purchases of securities held to maturity	-1,031	-450,661
Net (increase) decrease in interest-bearing bank deposits	-199,982	1,052,369
Net increase in federal funds sold and short-term investments	-2,736	-14,493
Net increase in loans	-1,060,864	-229,913
Purchase of life insurance contracts	-30,000	'
Purchases of property and equipment	-14,370	-25,855
Proceeds from sales of property and equipment	8,607	'
Proceeds from sales of other real estate	42,913	70,220
Other, net	4,273	-7,280
Net cash (used in) provided by investing activities	-1,115,076	307,029
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Net increase (decrease) in deposits	376,178	-689,317
Net increase in short-term borrowings	513,849	143,646
Repayments of long-term debt	-26,558	-26,469
Issuance of long-term debt	17,184	6,544
Dividends paid	-60,290	-61,000
Repurchase of common stock	-9,967	-115,000
Proceeds from exercise of stock options	962	582
Net cash provided by (used in) financing activities	811,358	-741,014
NET DECREASE IN CASH AND DUE FROM BANKS	-16,081	-22,798
CASH AND DUE FROM BANKS, BEGINNING	348,440	448,491
CASH AND DUE FROM BANKS, ENDING	332,359	425,693
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES	'	'
Assets acquired in settlement of loans	23,920	42,070
Transfers from available for sale securities to held to maturity securities	'	$983,162

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	1. Basis of Presentation
	The consolidated financial statements include the accounts of Hancock Holding Company and all other entities in which it has a controlling interest (the “Company”). The financial statements include all adjustments that are, in the opinion of management, necessary to present fairly the Company’s financial condition, results of operations, changes in stockholders’ equity and cash flows for the interim periods presented. Some financial information and disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the U.S. (U.S. GAAP) have been condensed or omitted in this Form 10-Q pursuant to Securities and Exchange Commission rules and regulations. These financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. Financial information reported in these financial statements is not necessarily indicative of the Company’s financial condition, results of operations, or cash flows for any other interim or annual period.
	Use of Estimates
	The accounting principles the Company follows and the methods for applying these principles conform with U.S. GAAP and with those generally practiced within the banking industry. These accounting principles require management to make estimates and assumptions about future events that affect the amounts reported in the consolidated financial statements and the accompanying notes. Actual results could differ from those estimates.
	Critical Accounting Policies and Estimates
	Income Taxes
	Income taxes are accounted for using the asset and liability method. Current tax liabilities or assets are recognized for the estimated income taxes payable or refundable on tax returns to be filed with respect to the current year. Deferred tax assets and liabilities are based on temporary differences between the financial statement carrying amounts and the tax bases of the Company’s assets and liabilities. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be realized or settled. Valuation allowances are established against deferred tax assets if, based on all available evidence, it is more likely than not that some or all of the assets will not be realized. The benefit of a position taken or expected to be taken in a tax return is recognized when it is more likely than not that the position will be sustained on its technical merits.
	The Company invests in projects that yield tax credits issued under the Qualified Zone Academy Bonds (QZAB), Qualified School Construction Bonds (QSCB), Federal and State New Market Tax Credit (NMTC), and Low-Income Housing Tax Credit (LIHTC) programs. Returns on these investments are generated through the receipt of federal and state tax credits. The tax credits are recorded as a reduction to the income tax provision in the year that they are earned. Tax credits from QZAB and QSCB bonds are generally earned over the life of the bonds in lieu of interest income. Credits on Federal NMTC investments are earned over the seven-year compliance period beginning with the year of investment. Credits on State NMTC investments are generally earned over a three- to five- year period depending upon the specific state program. Tax Credits for Low-Income Housing investments are earned over a ten-year period beginning with the year in which rental activity begins. These tax credits, if not used in the tax return for the year when the credits are first available for use, can be carried forward for 20 years. For those investments where the return of the principal is not expected, the equity investment is amortized over the life of the tax compliance period as a component of noninterest expense.
	Reportable Segment Disclosures
	Accounting standards require that information be reported about a company’s operating segments using a “management approach.” Reportable segments are identified in these standards as those revenue-producing components for which separate financial information is produced internally and which are subject to evaluation by the chief operating decision maker in deciding how to allocate resources to segments. On March 31, 2014, the Company combined its two state bank charters into one charter. Due to the charter change and consistent with its stated strategy that is focused on providing a consistent package of community banking products and services across all markets, the Company has identified its overall banking operations as its only reportable segment. Because the overall banking operations comprise substantially all of the consolidated operations, no separate segment disclosures are presented.
	There were no other material changes or developments with respect to methodologies that the Company uses when applying what management believes are critical accounting policies and developing critical accounting estimates as disclosed in our Annual Report on Form 10-K for the year ended December 31, 2013.

Securities

Securities	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Securities	'
	2. Securities
	The amortized cost and fair value of securities classified as available for sale and held to maturity follow (in thousands):
	Securities Available for Sale
		September 30, 2014								December 31, 2013
				Gross		Gross						Gross		Gross
		Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	US Treasury and government agency securities	$	300,257	$	446	$	1	$	300,702	$	504	$	2	$	1	$	505
	Municipal obligations		18,495		272		—		18,767		35,809		177		25		35,961
	Mortgage-backed securities		1,218,982		27,566		5,325		1,241,223		1,262,633		24,402		10,077		1,276,958
	CMOs		90,281		—		1,723		88,558		96,369		—		2,244		94,125
	Corporate debt securities		3,500		—		—		3,500		3,500		—		—		3,500
	Equity securities		8,784		877		1		9,660		9,965		785		27		10,723
		$	1,640,299	$	29,161	$	7,050	$	1,662,410	$	1,408,780	$	25,366	$	12,374	$	1,421,772
	Securities Held to Maturity
		September 30, 2014								December 31, 2013
				Gross		Gross						Gross		Gross
		Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	US Treasury and government agency securities	$	—	$	—	$	—	$	—	$	100,000	$	316	$	—	$	100,316
	Municipal obligations		183,379		2,911		1,709		184,581		193,189		919		6,436		187,672
	Mortgage-backed securities		926,163		12,426		1,258		937,331		1,003,327		296		4,671		998,952
	CMOs		1,141,418		5,888		15,999		1,131,307		1,314,836		1,062		26,254		1,289,644
		$	2,250,960	$	21,225	$	18,966	$	2,253,219	$	2,611,352	$	2,593	$	37,361	$	2,576,584
	The following table presents the amortized cost and fair value of debt securities at September 30, 2014 by contractual maturity (in thousands). Actual maturities will differ from contractual maturities because of rights to call or repay obligations with or without penalties and scheduled and unscheduled principal payments on mortgage-backed securities and CMOs.
		Amortized		Fair
		Cost		Value
	Debt Securities Available for Sale
	Due in one year or less	$	307,762	$	308,233
	Due after one year through five years		153,025		152,887
	Due after five years through ten years		218,513		225,794
	Due after ten years		952,215		965,836
	Total available for sale debt securities	$	1,631,515	$	1,652,750
		Amortized		Fair
		Cost		Value
	Debt Securities Held to Maturity
	Due in one year or less	$	5,302	$	5,317
	Due after one year through five years		638,277		626,915
	Due after five years through ten years		100,941		99,697
	Due after ten years		1,506,440		1,521,290
	Total held to maturity securities	$	2,250,960	$	2,253,219
	The Company held no securities classified as trading at September 30, 2014 or December 31, 2013.
	The details for securities classified as available for sale with unrealized losses for the periods indicated follow (in thousands):
	September 30, 2014	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	US Treasury and government agency securities	$	163	$	1	$	25	$	—	$	188	$	1
	Municipal obligations		—		—		—		—		—		—
	Mortgage-backed securities		64,485		514		125,977		4,811		190,462		5,325
	CMOs		48,604		324		39,954		1,399		88,558		1,723
	Equity securities		—		—		3		1		3		1
		$	113,252	$	839	$	165,959	$	6,211	$	279,211	$	7,050
	December 31, 2013	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	US Treasury and government agency securities	$	205	$	1	$	—	$	—	$	205	$	1
	Municipal obligations		7,975		25		—		—		7,975		25
	Mortgage-backed securities		376,350		7,164		49,061		2,913		425,411		10,077
	CMOs		94,125		2,244		—		—		94,125		2,244
	Equity securities		3,282		26		3		1		3,285		27
		$	481,937	$	9,460	$	49,064	$	2,914	$	531,001	$	12,374
The details for securities classified as held to maturity with unrealized losses for the periods indicated follow (in thousands):
Held to maturity
September 30, 2014	Losses < 12 months				Losses 12 months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
Municipal obligations	$	2,812	$	54	$	55,817	$	1,655	$	58,629	$	1,709
Mortgage-backed securities		—		—		128,802		1,258		128,802		1,258
CMOs		68,903		350		557,747		15,649		626,650		15,999
	$	71,715	$	404	$	742,366	$	18,562	$	814,081	$	18,966
December 31, 2013	Losses < 12 months				Losses 12 months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
Municipal obligations	$	131,499	$	6,311	$	2,878	$	125	$	134,377	$	6,436
Mortgage-backed securities		950,288		4,671		—		—		950,288		4,671
CMOs		947,061		25,088		175,633		1,166		1,122,694		26,254
	$	2,028,848	$	36,070	$	178,511	$	1,291	$	2,207,359	$	37,361
The unrealized losses relate to changes in market rates on fixed-rate debt securities since the respective purchase dates. In all cases, the indicated impairment would be recovered no later than the security’s maturity date or possibly earlier if the market price for the security increases with a reduction in the yield required by the market. None of the unrealized losses relate to the marketability of the securities or the issuer’s ability to meet contractual obligations. The Company believes it has adequate liquidity and, therefore, does not plan to and, more likely than not, will not be required to sell these securities before recovery of the indicated impairment. Accordingly, the unrealized losses on these securities have been determined to be temporary.
Securities with carrying values totaling $3.0 billion at September 30, 2014 and $3.1 billion at December 31, 2013 were pledged as collateral primarily to secure public deposits or securities sold under agreements to repurchase.

Loans_and_Allowance_for_Loan_L

Loans and Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Loans and Allowance for Loan Losses	'
	3. Loans and Allowance for Loan Losses
	Loans, net of unearned income, consisted of the following:
			September 30,			December 31,
			2014			2013
			(In thousands)
	Originated loans:
	Commercial non-real estate		$	4,806,740		$	4,113,837
	Construction and land development			974,442			752,381
	Commercial real estate			2,245,855			2,022,528
	Residential mortgages			1,635,462			1,196,256
	Consumer			1,623,069			1,409,130
	Total originated loans		$	11,285,568		$	9,494,132
	Acquired loans:
	Commercial non-real estate		$	769,226		$	926,997
	Construction and land development			110,294			142,931
	Commercial real estate			813,429			967,148
	Residential mortgages			37,739			315,340
	Consumer			51,488			119,603
	Total acquired loans		$	1,782,176		$	2,472,019
	Covered loans:
	Commercial non-real estate		$	11,171		$	23,390
	Construction and land development			11,166			20,229
	Commercial real estate			41,550			53,165
	Residential mortgages			185,289			209,018
	Consumer			31,654			52,864
	Total covered loans		$	280,830		$	358,666
	Total loans:
	Commercial non-real estate		$	5,587,137		$	5,064,224
	Construction and land development			1,095,902			915,541
	Commercial real estate			3,100,834			3,042,841
	Residential mortgages			1,858,490			1,720,614
	Consumer			1,706,211			1,581,597
	Total loans		$	13,348,574		$	12,324,817
	The following briefly describes the distinction between originated, acquired and covered loans and certain significant accounting policies relevant to each category.
	Originated loans
	Loans originated for investment are reported at the principal balance outstanding net of unearned income. Interest on loans and accretion of unearned income, including deferred loan fees, are computed in a manner that approximates a level yield on recorded principal. Interest on loans is recognized as income as earned.
	The accrual of interest on an originated loan is discontinued when, in management’s opinion, it is probable that the borrower will be unable to meet payment obligations as they become due, as well as when required by regulatory provisions. When accrual of interest is discontinued on a loan, all unpaid accrued interest is reversed and payments subsequently received are applied first to reduce principal, and interest income is recognized only for payments received after contractual principal has been satisfied. Loans are returned to accrual status when all the principal and interest contractually due are brought current and future payment performance is reasonably assured.
	Acquired loans
	Acquired loans are those purchased in the Whitney Holding Corporation acquisition on June 4, 2011. These loans were recorded at their estimated fair value at the acquisition date with no carryover of the related allowance for loan losses. The acquired loans were segregated between those considered to be performing (“acquired-performing”) and those with evidence of credit deterioration (“acquired-impaired”), based on such factors as past due status, nonaccrual status and credit risk ratings (rated substandard or worse). The acquired loans were further segregated into loan pools designed to facilitate the development of expected cash flows to be used in estimating their fair value.
	Acquired-performing loans were segregated into pools based on common risk characteristics such as loan type, credit risk ratings, and contractual interest rate and repayment terms. The major loan types included commercial and industrial loans not secured by real estate, real estate construction and land development loans, commercial real estate loans, residential mortgage loans, and consumer loans, with further segregation within certain loan types as appropriate. Aggregate cash flows, both principal and interest, expected to be generated by each loan pool were estimated based on key assumptions covering such factors as prepayments, default rates, and severity of loss given a default. These assumptions were developed using both Whitney Holding Corporation’s historical experience and the portfolio characteristics at acquisition as well as available market research.
	The difference at the acquisition date between the fair value and the contractual amounts due of an acquired-performing loan pool (the “fair value discount”) is accreted into income over the estimated life of the pool. Acquired-performing loans are placed on nonaccrual status and reported as nonperforming or past due using the same criteria applied to the originated portfolio.
	Acquired-impaired loans were segregated into pools by identifying loans with common credit risk profiles based primarily on characteristics such as loan type and market area in which originated. Loan types included most of the major types used for the acquired-performing portfolio. The acquired-impaired loans that had been originated in Louisiana and Texas were further disaggregated from loans originated in Mississippi, Alabama and Florida, in recognition of the differences in general economic conditions affecting borrowers in these market areas. The fair value estimate for each pool of acquired performing and acquired-impaired loans was based on the estimate of expected cash flows from the pool discounted at prevailing market rates.
	The excess of estimated cash flows expected to be collected from an acquired-impaired loan pool over the pool’s carrying value is referred to as the accretable yield and is recognized in interest income using an effective yield method over the estimated remaining life of the loan pool. Each pool of acquired-impaired loans is accounted for as a single asset with a single composite interest rate and an aggregate expectation of cash flows. Acquired-impaired loans in pools with an accretable yield and expected cash flows that are reasonably estimable are considered to be accruing and performing even though collection of contractual payments on loans within the pool may be in doubt, because the pool is the unit of accounting. Management recasts the estimate of cash flows expected to be collected on each acquired-impaired loan pool at each reporting date. If the present value of expected cash flows for a pool is less than its carrying value, impairment is recognized by an increase in the allowance for loan losses and a charge to the provision for loan losses. If the present value of expected cash flows for a pool is greater than its carrying value, any previously established allowance for loan losses is reversed and any remaining difference increases the accretable yield which will be taken into interest income over the remaining life of the loan pool. Acquired-impaired loans are generally not subject to individual evaluation for impairment and are not reported with impaired loans or troubled debt restructurings even if they would otherwise qualify for such treatment.
	Covered loans and the related loss share receivable
	The loans purchased in the 2009 acquisition of Peoples First Community Bank (Peoples First) are covered by two loss share agreements between the FDIC and the Company which afford the Company significant loss protection. These covered loans are accounted for as acquired-impaired loans as described above in the section on acquired loans. The Company treated all loans for the Peoples First acquisition as acquired-impaired loans based on the significant amount of deteriorating and nonperforming loans comprised mainly of adjustable rate mortgages and home equity loans located in Florida. The loss share receivable is measured separately from the related covered loans as it is not contractually embedded in the loans and is not transferrable if the loans are sold. The fair value of the loss share receivable at acquisition was estimated by discounting expected reimbursements for losses from the loans covered by the loss share agreements, including appropriate consideration of possible true-up payments to the FDIC at the expiration of the agreements.
	The loss share receivable is reviewed at each reporting period and updated prospectively as loss estimates related to covered loan pools change. Increases in expected reimbursements under the loss sharing agreements will lead to an increase in the loss share receivable. A decrease in expected reimbursements is reflected first as a reversal of any previously recorded increase in the loss share receivable on the covered loan pool with the remainder reflected as a reduction in the loss share receivable’s accretion rate. Increases and decreases in the loss share receivable related to changes in loss estimates result in reductions in or additions to the provision for loan losses, which serves to offset the impact on the provision from impairments or impairment reversals recognized on the underlying covered loan pool. The excess (or shortfall) of expected claims as compared to the carrying value of the loss share receivable is accreted (amortized) into noninterest income over the shorter of the remaining life of the covered loan pool or the life of the loss share agreement. The impact on operations of a reduction in the loss share receivable’s accretion rate is associated with an increase in the accretable yield on the underlying loan pool. The indemnification asset is reduced as cash is received from the FDIC related to losses incurred on covered assets.
	The following schedule shows activity in the loss share receivable for the nine months ended September 30, 2014 and 2013 (in thousands):
			Nine Months Ended
			September 30,			September 30,
			2014			2013
	Balance, January 1		$	113,834		$	177,844
	Amortization			(9,989	)		(590	)
	Charge-offs, write-downs and other losses (recoveries)			(793	)		(190	)
	External expenses qualifying under loss share agreement			3,325			7,918
	Changes due to changes in cash flow projections			(14,569	)		—
	Settlement of disallowed loss claims			(10,268	)		—
	Net payments to (from) FDIC			366			(60,886	)
	Ending balance		$	81,906		$	124,096
	The loss share agreements contain specific terms and conditions regarding the management of the covered assets that the Company must follow in order to receive reimbursement for losses from the FDIC. During the second quarter of 2014, the Company reached a settlement agreement to reimburse the FDIC $10.3 million for certain claims previously received under the agreements. The disagreement arose from a targeted review of the Company’s compliance with the terms of the agreements and related to the matter in which certain assets were administered and losses were calculated. The FDIC had suspended processing the Company’s claims as of September 2013 pending settlement of these issues and outstanding claims. During the third quarter, the settlement was paid and the FDIC began payment of claims. The total due from the FDIC for the period December 2013 through August 2014 is $21.1 million.
	The following schedule shows activity in the allowance for loan losses by portfolio segment for the nine months ended September 30, 2014 and 2013 as well as the corresponding recorded investment in loans at the end of each period.
			Commercial			Construction			Commercial			Residential			Consumer			Total
			non-real			and land			real estate			mortgages
			estate			development
(In thousands)		Nine Months Ended September 30, 2014
Originated loans
Allowance for loan losses:
Beginning balance		$	33,091		$	6,180		$	20,649		$	6,892		$	12,073		$	78,885
Charge-offs			(4,690	)		(2,615	)		(2,255	)		(1,793	)		(11,920	)		(23,273	)
Recoveries			2,118			1,220			1,231			501			3,722			8,792
Net provision for loan losses			3,929			2,151			(3,231	)		3,647			10,921			17,417
Ending balance		$	34,448		$	6,936		$	16,394		$	9,247		$	14,796		$	81,821
Ending balance:
Individually evaluated for impairment		$	24		$	250		$	98		$	382		$	—		$	754
Collectively evaluated for impairment			34,424			6,686			16,296			8,865			14,796			81,067
Loans:
Ending balance:		$	4,806,740		$	974,442		$	2,245,855		$	1,635,462		$	1,623,069		$	11,285,568
Individually evaluated for impairment			5,582			6,617			14,486			2,712			—			29,397
Collectively evaluated for impairment			4,801,158			967,825			2,231,369			1,632,750			1,623,069			11,256,171
Acquired loans
Allowance for loan losses:
Beginning balance		$	1,603		$	10		$	34		$	—		$	—		$	1,647
Charge-offs			—			—			—			—			—			—
Recoveries			—			—			—			—			—			—
Net provision for loan losses			5,800			1,436			57			(4	)		182			7,471
Ending balance		$	7,403		$	1,446		$	91		$	(4	)	$	182		$	9,118
Ending balance:
Individually evaluated for impairment		$	92		$	426		$	46		$	—		$	—		$	564
Amounts related to acquired-impaired loans			—			—			—			—			—			—
Collectively evaluated for impairment			7,311			1,020			45			(4	)		182			8,554
Loans:
Ending balance:		$	769,226		$	110,294		$	813,429		$	37,739		$	51,488		$	1,782,176
Individually evaluated for impairment			931			2,284			458			28			—			3,701
Acquired-impaired loans			4,064			19,200			27,392			5,038			143			55,837
Collectively evaluated for impairment			764,231			88,810			785,579			32,673			51,345			1,722,638
		Commercial			Construction			Commercial			Residential			Consumer			Total
		non-real			and land			real estate			mortgages
		estate			development
(In thousands)		Nine Months Ended September 30, 2014
Covered loans
Allowance for loan losses:
Beginning balance		$	2,323		$	2,655		$	10,929		$	27,989		$	9,198		$	53,094
Charge-offs			(176	)		(350	)		(4,480	)		(677	)		(1,192	)		(6,875	)
Recoveries			467			1,504			1,408			1			370			3,750
Net provision for loan losses			(79	)		(138	)		(125	)		(257	)		(167	)		(766	)
Decrease in FDIC loss share receivable			(1,507	)		(2,404	)		(2,418	)		(4,873	)		(3,368	)		(14,570	)
Ending balance		$	1,028		$	1,267		$	5,314		$	22,183		$	4,841		$	34,633
Ending balance:
Individually evaluated for impairment		$	—		$	—		$	—		$	—		$	—		$	—
Amounts related to acquired-impaired loans			1,028			1,267			5,314			22,183			4,841			34,633
Collectively evaluated for impairment			—			—			—			—			—			—
Loans:
Ending balance:		$	11,171		$	11,166		$	41,550		$	185,289		$	31,654		$	280,830
Individually evaluated for impairment			—			—			—			—			—			—
Acquired-impaired loans			11,171			11,166			41,550			185,289			31,654			280,830
Collectively evaluated for impairment			—			—			—			—			—			—
Total loans
Allowance for loan losses:
Beginning balance		$	37,017		$	8,845		$	31,612		$	34,881		$	21,271		$	133,626
Charge-offs			(4,866	)		(2,965	)		(6,735	)		(2,470	)		(13,112	)		(30,148	)
Recoveries			2,585			2,724			2,639			502			4,092			12,542
Net provision for loan losses			9,650			3,449			(3,299	)		3,386			10,936			24,122
Decrease in FDIC loss share receivable			(1,507	)		(2,404	)		(2,418	)		(4,873	)		(3,368	)		(14,570	)
Ending balance		$	42,879		$	9,649		$	21,799		$	31,426		$	19,819		$	125,572
Ending balance:
Individually evaluated for impairment		$	116		$	676		$	144		$	382		$	—		$	1,318
Amounts related to acquired-impaired loans			1,028			1,267			5,314			22,183			4,841			34,633
Collectively evaluated for impairment			41,735			7,706			16,341			8,861			14,978			89,621
Loans:
Ending balance:		$	5,587,137		$	1,095,902		$	3,100,834		$	1,858,490		$	1,706,211		$	13,348,574
Individually evaluated for impairment			6,513			8,901			14,944			2,740			—			33,098
Acquired-impaired loans			15,235			30,366			68,942			190,327			31,797			336,667
Collectively evaluated for impairment			5,565,389			1,056,635			3,016,948			1,665,423			1,674,414			12,978,809
		Commercial			Construction			Commercial			Residential			Consumer			Total
		non-real			and land			real estate			mortgages
		estate			development
(In thousands)		Nine Months Ended September 30, 2013
Originated loans
Allowance for loan losses:
Beginning balance		$	20,775		$	11,415		$	26,959		$	6,406		$	13,219		$	78,774
Charge-offs			(5,199	)		(7,548	)		(3,718	)		(1,549	)		(13,372	)		(31,386	)
Recoveries			3,381			1,243			2,340			991			4,336			12,291
Net provision for loan losses			11,152			2,072			(3,698	)		64			8,152			17,742
Ending balance		$	30,109		$	7,182		$	21,883		$	5,912		$	12,335		$	77,421
Ending balance:
Individually evaluated for impairment		$	325		$	211		$	946		$	—		$	—		$	1,482
Collectively evaluated for impairment			29,784			6,971			20,937			5,912			12,335			75,939
Loans:
Ending balance:		$	3,633,490		$	738,983		$	1,816,402		$	1,124,649		$	1,387,243		$	8,700,767
Individually evaluated for impairment			8,911			16,044			21,170			—			—			46,125
Collectively evaluated for impairment			3,624,579			722,939			1,795,232			1,124,649			1,387,243			8,654,642
Acquired loans
Allowance for loan losses:
Beginning balance		$	788		$	—		$	—		$	—		$	—		$	788
Charge-offs			—			—			—			—			—			—
Recoveries			—			—			—			—			—			—
Net provision for loan losses			(788	)		—			463			—			—			(325	)
Ending balance		$	—		$	—		$	463		$	—		$	—		$	463
Ending balance:
Individually evaluated for impairment		$	—		$	—		$	463		$	—		$	—		$	463
Amounts related to acquired-impaired loans			—			—			—			—			—			—
Collectively evaluated for impairment			—			—			—			—			—			—
Loans:
Ending balance:		$	967,485		$	158,228		$	1,038,287		$	347,054		$	130,649		$	2,641,703
Individually evaluated for impairment			2,179			730			2,371			502			—			5,782
Acquired-impaired loans			18,967			15,080			25,432			5,387			105			64,971
Collectively evaluated for impairment			946,339			142,418			1,010,484			341,165			130,544			2,570,950
		Commercial			Construction			Commercial			Residential			Consumer			Total
		non-real			and land			real estate			mortgages
		estate			development
(In thousands)		Nine Months Ended September 30, 2013
Covered loans
Allowance for loan losses:
Beginning balance		$	2,162		$	5,623		$	9,433		$	30,471		$	8,920		$	56,609
Charge-offs			(681	)		(1,784	)		(4,316	)		(947	)		(1,145	)		(8,873	)
Recoveries			90			554			2,395			13			67			3,119
Net provision for loan losses			(328	)		(1,600	)		1,197			4,723			3,995			7,987
Increase (Decrease) in FDIC loss share receivable			447			(314	)		(732	)		1,261			835			1,497
Ending balance		$	1,690		$	2,479		$	7,977		$	35,521		$	12,672		$	60,339
Ending balance:
Individually evaluated for impairment		$	—		$	—		$	—		$	—		$	—		$	—
Amounts related to acquired-impaired loans			1,690			2,479			7,977			35,521			12,672			60,339
Collectively evaluated for impairment			—			—			—			—			—			—
Loans:
Ending balance:		$	24,340		$	23,197		$	60,280		$	223,494		$	60,691		$	392,002
Individually evaluated for impairment			—			—			—			—			—			—
Acquired-impaired loans			24,340			23,197			60,280			223,494			60,691			392,002
Collectively evaluated for impairment			—			—			—			—			—			—
Total loans
Allowance for loan losses:
Beginning balance		$	23,725		$	17,038		$	36,392		$	36,877		$	22,139		$	136,171
Charge-offs			(5,880	)		(9,332	)		(8,034	)		(2,496	)		(14,517	)		(40,259	)
Recoveries			3,471			1,797			4,735			1,004			4,403			15,410
Net provision for loan losses			10,036			472			(2,038	)		4,787			12,147			25,404
Increase (Decrease) in FDIC loss share receivable			447			(314	)		(732	)		1,261			835			1,497
Ending balance		$	31,799		$	9,661		$	30,323		$	41,433		$	25,007		$	138,223
Ending balance:
Individually evaluated for impairment		$	325		$	211		$	1,409		$	—		$	—		$	1,945
Amounts related to acquired-impaired loans			1,690			2,479			7,977			35,521			12,672			60,339
Collectively evaluated for impairment			29,784			6,971			20,937			5,912			12,335			75,939
Loans:
Ending balance:		$	4,625,315		$	920,408		$	2,914,969		$	1,695,197		$	1,578,583		$	11,734,472
Individually evaluated for impairment			11,090			16,774			23,541			502			—			51,907
Acquired-impaired loans			43,307			38,277			85,712			228,881			60,796			456,973
Collectively evaluated for impairment			4,570,918			865,357			2,805,716			1,465,814			1,517,787			11,225,592
The following tables show the composition of nonaccrual loans by portfolio segment and class. Acquired-impaired and certain covered loans are considered to be performing due to the application of the accretion method and are excluded from the table. Covered loans accounted for using the cost recovery method do not have an accretable yield and are included below as nonaccrual loans. Acquired-performing loans that have subsequently been placed on nonaccrual status are also included below.
		September 30,			December 31,
Nonaccrual Loans		2014			2013
		(In thousands)
Originated loans:
Commercial non-real estate		$	9,279		$	10,119
Construction and land development			6,083			13,171
Commercial real estate			26,432			32,772
Residential mortgages			21,326			13,449
Consumer			5,242			4,802
Total originated loans		$	68,362		$	74,313
Acquired loans:
Commercial non-real estate		$	1,857		$	3,209
Construction and land development			3,275			1,990
Commercial real estate			4,210			6,525
Residential mortgages			1,353			8,262
Consumer			877			1,814
Total acquired loans		$	11,572		$	21,800
Covered loans:
Commercial non-real estate		$	—		$	2
Construction and land development			1,539			1,539
Commercial real estate			1,107			1,163
Residential mortgages			394			544
Consumer			180			296
Total covered loans		$	3,220		$	3,544
Total loans:
Commercial non-real estate		$	11,136		$	13,330
Construction and land development			10,897			16,700
Commercial real estate			31,749			40,460
Residential mortgages			23,073			22,255
Consumer			6,299			6,912
Total loans		$	83,154		$	99,657
The estimated amount of interest that would have been recorded on nonaccrual loans had the loans not been classified as nonaccrual in the nine months ended September 30, 2014 was approximately $1 million. Interest actually received and recorded as income on nonaccrual loans during the nine months ended September 30, 2014 was approximately $1 million.
Nonaccrual loans include loans modified in troubled debt restructurings (TDRs) of $10 million. Total TDRs were $18 million as of September 30, 2014 and $25 million at December 31, 2013. Modified acquired-impaired loans are not removed from their accounting pool and accounted for as TDRs, even if those loans would otherwise be deemed TDRs.
The tables below detail TDRs that were modified during the nine months ended September 30, 2014 and September 30, 2013 by portfolio segment and TDRs that subsequently defaulted within twelve months of modification (dollar amounts in thousands). All TDRs are rated substandard and individually evaluated for impairment.
		Nine Months Ended
		September 30, 2014									September 30, 2013
Troubled Debt Restructurings:		Number of			Pre-Modification			Post-Modification			Number of			Pre-Modification			Post-Modification
		Contracts			Outstanding			Outstanding			Contracts			Outstanding			Outstanding
					Recorded			Recorded						Recorded			Recorded
					Investment			Investment						Investment			Investment
Originated loans:
Commercial non-real estate			—		$	—		$	—			1		$	925		$	920
Construction and land development			—			—			—			—			—			—
Commercial real estate			2			2,430			2,385			5			1,844			1,789
Residential mortgages			4			1,495			848			2			971			854
Consumer			—			—			—			—			—			—
Total originated loans			6		$	3,925		$	3,233			8		$	3,740		$	3,563
Acquired loans:
Commercial non-real estate			—		$	—		$	—			—		$	—		$	—
Construction and land development			—			—			—			—			—			—
Commercial real estate			—			—			—			1			512			501
Residential mortgages			—			—			—			1			515			493
Consumer			—			—			—			—			—			—
Total acquired loans			—		$	—		$	—			2		$	1,027		$	994
Covered loans:
Commercial non-real estate			—		$	—		$	—			—		$	—		$	—
Construction and land development			—			—			—			—			—			—
Commercial real estate			—			—			—			—			—			—
Residential mortgages			—			—			—			—			—			—
Consumer			—			—			—			—			—			—
Total covered loans			—		$	—		$	—			—		$	—		$	—
Total loans:
Commercial non-real estate			—		$	—		$	—			1		$	925		$	920
Construction and land development			—			—			—			—			—			—
Commercial real estate			2			2,430			2,385			6			2,356			2,290
Residential mortgages			4			1,495			848			3			1,486			1,347
Consumer			—			—			—			—			—			—
Total loans			6		$	3,925		$	3,233			10		$	4,767		$	4,557
		Nine Months Ended
		September 30, 2014						September 30, 2013
Troubled Debt Restructurings That Subsequently Defaulted:		Number of			Recorded			Number of			Recorded
		Contracts			Investment			Contracts			Investment
Originated loans:
Commercial non-real estate			1		$	909			—		$	—
Construction and land development			—			—			—			—
Commercial real estate			—			—			—			—
Residential mortgages			—			—			—			—
Consumer			—			—			—			—
Total originated loans			1		$	909			—		$	—
Acquired loans:
Commercial non-real estate			—		$	—			—		$	—
Construction and land development			—			—			—			—
Commercial real estate			—			—			—			—
Residential mortgages			—			—			—			—
Consumer			—			—			—			—
Total acquired loans			—		$	—			—		$	—
Covered loans:
Commercial non-real estate			—		$	—			—		$	—
Construction and land development			—			—			—			—
Commercial real estate			—			—			—			—
Residential mortgages			—			—			—			—
Consumer			—			—			—			—
Total covered loans			—		$	—			—		$	—
Total loans:
Commercial non-real estate			1		$	909			—		$	—
Construction and land development			—			—			—			—
Commercial real estate			—			—			—			—
Residential mortgages			—			—			—			—
Consumer			—			—			—			—
Total loans			1		$	909			—		$	—
Those loans that are determined to be impaired and have balances of $1 million or more are individually evaluated for impairment. The tables below present loans that are individually evaluated for impairment disaggregated by class at September 30, 2014 and December 31, 2013:
September 30, 2014		Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Income
					Balance						Investment			Recognized
		(In thousands)
Originated loans:
With no related allowance recorded:
Commercial non-real estate		$	1,498		$	2,111		$	—		$	1,157		$	31
Construction and land development			3,320			5,459			—			3,218			112
Commercial real estate			10,502			13,011			—			8,428			246
Residential mortgages			263			647			—			88			1
Consumer			—			—			—			—			—
			15,583			21,228			—			12,891			390
With an allowance recorded:
Commercial non-real estate		$	4,084		$	4,173		$	24		$	5,922			77
Construction and land development			3,297			3,815			250			6,578			100
Commercial real estate			3,984			4,304			98			7,417			75
Residential mortgages			2,449			2,758			382			2,189			28
Consumer			—			—			—			—			—
			13,814			15,050			754			22,106			280
Total:
Commercial non-real estate			5,582			6,284			24			7,079			108
Construction and land development			6,617			9,274			250			9,796			212
Commercial real estate			14,486			17,315			98			15,845			321
Residential mortgages			2,712			3,405			382			2,277			29
Consumer			—			—			—			—			—
Total originated loans		$	29,397		$	36,278		$	754		$	34,997		$	670
Acquired loans:
With no related allowance recorded:
Commercial non-real estate		$	—		$	1,730		$	—		$	357		$	—
Construction and land development			—			—			—			121			—
Commercial real estate			—			—			—			311			—
Residential mortgages			28			68			—			88			—
Consumer			—			—			—			—			—
			28			1,798			—			877			—
With an allowance recorded:
Commercial non-real estate			931			1,070			92		$	1,304			118
Construction and land development			2,284			4,835			426			1,130			45
Commercial real estate			458			493			46			1,305			61
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
			3,673			6,398			564			3,739			224
Total:
Commercial non-real estate			931			2,800			92			1,661			118
Construction and land development			2,284			4,835			426			1,251			45
Commercial real estate			458			493			46			1,616			61
Residential mortgages			28			68			—			88			—
Consumer			—			—			—			—			—
Total acquired loans		$	3,701		$	8,196		$	564		$	4,616		$	224
September 30, 2014		Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Income
					Balance						Investment			Recognized
Covered loans:
With no related allowance recorded:
Commercial non-real estate		$	—		$	—		$	—		$	—		$	—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
			—			—			—			—			—
With an allowance recorded:
Commercial non-real estate			—			—			—			—			—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
			—			—			—			—			—
Total:
Commercial non-real estate			—			—			—			—			—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
Total covered loans		$	—		$	—		$	—		$	—		$	—
Total loans:
With no related allowance recorded:
Commercial non-real estate		$	1,498		$	3,841		$	—		$	1,514		$	31
Construction and land development			3,320			5,459			—			3,339			112
Commercial real estate			10,502			13,011			—			8,739			246
Residential mortgages			291			715			—			176			1
Consumer			—			—			—			—			—
			15,611			23,026			—			13,768			390
With an allowance recorded:
Commercial non-real estate			5,015			5,243			116			7,226			195
Construction and land development			5,581			8,650			676			7,708			145
Commercial real estate			4,442			4,797			144			8,722			136
Residential mortgages			2,449			2,758			382			2,189			28
Consumer			—			—			—			—			—
			17,487			21,448			1,318			25,845			504
Total:
Commercial non-real estate			6,513			9,084			116			8,740			226
Construction and land development			8,901			14,109			676			11,047			257
Commercial real estate			14,944			17,808			144			17,461			382
Residential mortgages			2,740			3,473			382			2,365			29
Consumer			—			—			—			—			—
Total loans		$	33,098		$	44,474		$	1,318		$	39,613		$	894
December 31, 2013		Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Income
					Balance						Investment			Recognized
		(In thousands)
Originated loans:
With no related allowance recorded:
Commercial non-real estate		$	329		$	442		$	—		$	235		$	18
Construction and land development			4,101			5,131			—			2,780			82
Commercial real estate			5,321			7,458			—			15,886			374
Residential mortgages			—			—			—			262			—
Consumer			—			—			—			1,013			—
			9,751			13,031			—			20,176			474
With an allowance recorded:
Commercial non-real estate			4,965			5,303			477			8,936			180
Construction and land development			6,498			8,343			22			2,549			—
Commercial real estate			8,708			9,090			268			19,683			460
Residential mortgages			605			620			1			228			—
Consumer			—			—			—			1,025			—
			20,776			23,356			768			32,421			640
Total:
Commercial non-real estate			5,294			5,745			477			9,171			198
Construction and land development			10,599			13,474			22			5,329			82
Commercial real estate			14,029			16,548			268			35,569			834
Residential mortgages			605			620			1			490			—
Consumer			—			—			—			2,038			—
Total originated loans		$	30,527		$	36,387		$	768		$	52,597		$	1,114
Acquired loans:
With no related allowance recorded:
Commercial non-real estate		$	2,141		$	3,275		$	—		$	865		$	8
Construction and land development			728			1,142			—			296			3
Commercial real estate			1,865			2,634			—			1,339			49
Residential mortgages			473			507			—			407			—
Consumer			—			—			—			—			—
			5,207			7,558			—			2,907			60
With an allowance recorded:
Commercial non-real estate			—			—			—			2,747			63
Construction and land development			—			—			—			157			—
Commercial real estate			—			—			—			2,663			—
Residential mortgages			—			—			—			845			—
Consumer			—			—			—			—			—
			—			—			—			6,412			63
Total:
Commercial non-real estate			2,141			3,275			—			3,612			71
Construction and land development			728			1,142			—			453			3
Commercial real estate			1,865			2,634			—			4,002			49
Residential mortgages			473			507			—			1,252			—
Consumer			—			—			—			—			—
Total acquired loans		$	5,207		$	7,558		$	—		$	9,319		$	123
					Unpaid						Average			Interest
		Recorded			Principal			Related			Recorded			Income
December 31, 2013		Investment			Balance			Allowance			Investment			Recognized
Covered loans:
With no related allowance recorded:
Commercial non-real estate		$	—		$	—		$	—		$	—		$	—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
			—			—			—			—			—
With an allowance recorded:
Commercial non-real estate			—			—			—			—			—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
			—			—			—			—			—
Total:
Commercial non-real estate			—			—			—			—			—
Construction and land development			—			—			—			—			—
Commercial real estate			—			—			—			—			—
Residential mortgages			—			—			—			—			—
Consumer			—			—			—			—			—
Total covered loans		$	—		$	—		$	—		$	—		$	—
Total loans:
With no related allowance recorded:
Commercial non-real estate		$	2,470		$	3,717		$	—		$	1,100		$	26
Construction and land development			4,829			6,273			—			3,076			85
Commercial real estate			7,186			10,092			—			17,225			423
Residential mortgages			473			507			—			669			—
Consumer			—			—			—			1,013			—
			14,958			20,589			—			23,083			534
With an allowance recorded:
Commercial non-real estate			4,965			5,303			477			11,683			243
Construction and land development			6,498			8,343			22			2,706			—
Commercial real estate			8,708			9,090			268			22,346			460
Residential mortgages			605			620			1			1,073			—
Consumer			—			—			—			1,025			—
			20,776			23,356			768			38,833			703
Total:
Commercial non-real estate			7,435			9,020			477			12,783			269
Construction and land development			11,327			14,616			22			5,782			85
Commercial real estate			15,894			19,182			268			39,571			883
Residential mortgages			1,078			1,127			1			1,742			—
Consumer			—			—			—			2,038			—
Total loans		$	35,734		$	43,945		$	768		$	61,916		$	1,237
Covered loans and acquired-impaired loans with an accretable yield are considered to be current in the following delinquency table. Certain covered loans accounted for using the cost recovery method are disclosed according to their contractual payment status below. The following tables present the age analysis of past due loans at September 30, 2014 and December 31, 2013:
																				Recorded
								Greater than												investment
		30-59 days			60-89 days			90 days			Total						Total			> 90 days
September 30, 2014		past due			past due			past due			past due			Current			Loans			and still accruing
											(In thousands)
Originated loans:
Commercial non-real estate		$	4,137		$	4,039		$	3,111		$	11,287		$	4,795,453		$	4,806,740		$	259
Construction and land development			1,159			651			6,185			7,995			966,447			974,442			1,443
Commercial real estate			3,524			2,170			12,271			17,965			2,227,890			2,245,855			257
Residential mortgages			606			5,071			10,503			16,180			1,619,282			1,635,462			220
Consumer			4,539			2,556			4,290			11,385			1,611,684			1,623,069			2,970
Total		$	13,965		$	14,487		$	36,360		$	64,812		$	11,220,756		$	11,285,568		$	5,149
Acquired loans:
Commercial non-real estate		$	151		$	95		$	1,734		$	1,980		$	767,246		$	769,226		$	—
Construction and land development			231			1,649			1,400			3,280			107,014			110,294			17
Commercial real estate			522			641			3,534			4,697			808,732			813,429			1,471
Residential mortgages			27			—			228			255			37,484			37,739			—
Consumer			358			241			593			1,192			50,296			51,488			30
Total		$	1,289		$	2,626		$	7,489		$	11,404		$	1,770,772		$	1,782,176		$	1,518
Covered loans:
Commercial non-real estate		$	—		$	—		$	—		$	—		$	11,171		$	11,171		$	—
Construction and land development			—			—			—			—			11,166			11,166			—
Commercial real estate			—			—			—			—			41,550			41,550			—
Residential mortgages			—			149			—			149			185,140			185,289			—
Consumer			1			—			35			36			31,618			31,654			—
Total		$	1		$	149		$	35		$	185		$	280,645		$	280,830		$	—
Total loans:
Commercial non-real estate		$	4,288		$	4,134		$	4,845		$	13,267		$	5,573,870		$	5,587,137		$	259
Construction and land development			1,390			2,300			7,585			11,275			1,084,627			1,095,902			1,460
Commercial real estate			4,046			2,811			15,805			22,662			3,078,172			3,100,834			1,728
Residential mortgages			633			5,220			10,731			16,584			1,841,906			1,858,490			220
Consumer			4,898			2,797			4,918			12,613			1,693,598			1,706,211			3,000
Total		$	15,255		$	17,262		$	43,884		$	76,401		$	13,272,173		$	13,348,574		$	6,667
																				Recorded
								Greater than												investment
		30-59 days			60-89 days			90 days			Total						Total			> 90 days
December 31, 2013		past due			past due			past due			past due			Current			Loans			and still accruing
											(In thousands)
Originated loans:
Commercial non-real estate		$	11,645		$	1,203		$	4,803		$	17,651		$	4,096,186		$	4,113,837		$	521
Construction and land development			5,877			1,264			5,970			13,111			739,270			752,381			—
Commercial real estate			8,178			5,744			14,620			28,542			1,993,986			2,022,528			420
Residential mortgages			12,410			3,870			3,540			19,820			1,176,436			1,196,256			—
Consumer			8,798			1,913			3,823			14,534			1,394,596			1,409,130			2,344
Total		$	46,908		$	13,994		$	32,756		$	93,658		$	9,400,474		$	9,494,132		$	3,285
Acquired loans:
Commercial non-real estate		$	1,982		$	2,332		$	1,467		$	5,781		$	921,216		$	926,997		$	541
Construction and land development			862			1,529			1,161			3,552			139,379			142,931			541
Commercial real estate			3,742			1,345			9,026			14,113			953,035			967,148			5,853
Residential mortgages			5,632			2,698			5,503			13,833			301,507			315,340			72
Consumer			1,029			120			1,013			2,162			117,441			119,603			82
Total		$	13,247		$	8,024		$	18,170		$	39,441		$	2,432,578		$	2,472,019		$	7,089
Covered loans:
Commercial non-real estate		$	—		$	—		$	—		$	—		$	23,390		$	23,390		$	—
Construction and land development			—			—			1,539			1,539			18,690			20,229			—
Commercial real estate			—			—			675			675			52,490			53,165			—
Residential mortgages			—			—			3			3			209,015			209,018			—
Consumer			—			—			—			—			52,864			52,864			—
Total		$	—		$	—		$	2,217		$	2,217		$	356,449		$	358,666		$	—
Total loans:
Commercial non-real estate		$	13,627		$	3,535		$	6,270		$	23,432		$	5,040,792		$	5,064,224		$	1,062
Construction and land development			6,739			2,793			8,670			18,202			897,339			915,541			541
Commercial real estate			11,920			7,089			24,321			43,330			2,999,511			3,042,841			6,273
Residential mortgages			18,042			6,568			9,046			33,656			1,686,958			1,720,614			72
Consumer			9,827			2,033			4,836			16,696			1,564,901			1,581,597			2,426
Total		$	60,155		$	22,018		$	53,143		$	135,316		$	12,189,501		$	12,324,817		$	10,374
The following tables present the credit quality indicators of the Company’s various classes of loans at September 30, 2014 and December 31, 2013.
Commercial Non-Real Estate Credit Exposure
Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
Grade:
Pass		$	4,656,899		$	698,111		$	1,856		$	5,356,866		$	3,990,320		$	846,134		$	10,477		$	4,846,931
Pass-Watch			58,894			32,372			—			91,266			46,734			44,105			9			90,848
Special Mention			26,869			26,635			521			54,025			41,812			19,915			2,897			64,624
Substandard			63,959			12,108			8,794			84,861			34,276			16,125			9,662			60,063
Doubtful			119			—			—			119			695			718			345			1,758
Loss			—			—			—			—			—			—			—			—
Total		$	4,806,740		$	769,226		$	11,171		$	5,587,137		$	4,113,837		$	926,997		$	23,390		$	5,064,224
Construction Credit Exposure
Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
Grade:
Pass		$	923,800		$	82,067		$	2,323		$	1,008,190		$	709,261		$	112,773		$	1		$	822,035
Pass-Watch			17,576			2,911			1,000			21,487			7,817			1,907			1,226			10,950
Special Mention			5,832			5,737			29			11,598			3,926			9,409			276			13,611
Substandard			27,234			19,579			7,814			54,627			31,377			18,842			11,498			61,717
Doubtful			—			—			—			—			—			—			7,228			7,228
Loss			—			—			—			—			—			—			—			—
Total		$	974,442		$	110,294		$	11,166		$	1,095,902		$	752,381		$	142,931		$	20,229		$	915,541
Commercial Real Estate Credit Exposure
Credit Risk Profile by Internally Assigned Grade
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
Grade:
Pass		$	2,048,886		$	758,092		$	6,805		$	2,813,783		$	1,864,115		$	896,578		$	1,678		$	2,762,371
Pass-Watch			83,729			8,725			5,811			98,265			49,578			9,530			10,266			69,374
Special Mention			25,842			9,029			863			35,734			15,785			19,798			1,999			37,582
Substandard			87,369			37,583			28,039			152,991			93,034			41,242			31,350			165,626
Doubtful			29			—			32			61			16			—			7,872			7,888
Loss			—			—			—			—			—			—			—			—
Total		$	2,245,855		$	813,429		$	41,550		$	3,100,834		$	2,022,528		$	967,148		$	53,165		$	3,042,841
Residential Mortgage Credit Exposure
Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
Performing		$	1,624,959		$	37,511		$	185,289		$	1,847,759		$	1,182,266		$	307,078		$	209,015		$	1,698,359
Nonperforming			10,503			228			—			10,731			13,990			8,262			3			22,255
Total		$	1,635,462		$	37,739		$	185,289		$	1,858,490		$	1,196,256		$	315,340		$	209,018		$	1,720,614
Consumer Credit Exposure
Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
Performing		$	1,618,779		$	50,895		$	31,619		$	1,701,293		$	1,404,032		$	117,789		$	52,864		$	1,574,685
Nonperforming			4,290			593			35			4,918			5,098			1,814			—			6,912
Total		$	1,623,069		$	51,488		$	31,654		$	1,706,211		$	1,409,130		$	119,603		$	52,864		$	1,581,597
Loan review uses a risk-focused continuous monitoring program that provides for an independent, objective and timely review of credit risk within the company’s loan portfolio. Below are the definitions of the Company’s internally assigned grades:
Commercial:
	•		Pass - Loans properly approved, documented, collateralized, and performing which do not reflect an abnormal credit risk.
	•		Pass - Watch - Credits in this category are of sufficient risk to cause concern. This category is reserved for credits that display negative performance trends. The “Watch” grade should be regarded as a transition category.
	•		Special Mention - These credits exhibit some signs of “Watch,” but to a greater magnitude. These credits constitute an undue and unwarranted credit risk, but not to a point of justifying a classification of “Substandard.” They have weaknesses that, if not checked or corrected, weaken the asset or inadequately protect the bank.
	•		Substandard - These credits constitute an unacceptable risk to the bank. They have recognized credit weaknesses that jeopardize the repayment of the debt. Repayment sources are marginal or unclear.
	•		Doubtful - A doubtful credit has all of the weaknesses inherent in one classified “Substandard” with the added characteristic that weaknesses make collection in full highly questionable or improbable.
	•		Loss - Credits classified as Loss are considered uncollectable and are charged off promptly once so classified.
Residential and Consumer:
	•		Performing - Loans on which payments of principal and interest are less than 90 days past due.
	•		Nonperforming - A nonperforming loan is a loan that is in default or close to being in default and there are good reasons to doubt that payments will be made in full. All loans rated as nonaccrual loans are also classified as nonperforming.
Changes in the carrying amount of acquired-impaired loans and accretable yield are presented in the following table for the nine months ended September 30, 2014 and the year ended December 31, 2013:
		September 30, 2014												December 31, 2013
		Covered						Noncovered						Covered						Noncovered
		Carrying						Carrying						Carrying						Carrying
		Amount			Accretable			Amount			Accretable			Amount			Accretable			Amount			Accretable
		of Loans			Yield			of Loans			Yield			of Loans			Yield			of Loans			Yield
(In thousands)
Balance at beginning of period		$	358,666		$	122,715		$	68,075		$	131,370		$	515,823		$	115,594		$	141,201		$	203,186
Additions			—			—			—			—			—			—			—			—
Payments received, net			(92,890	)		(953	)		(47,979	)		(28,487	)		(189,987	)		(1,298	)		(116,187	)		(47,330	)
Accretion			15,054			(15,054	)		35,741			(35,741	)		32,830			(32,830	)		43,061			(43,061	)
Increase (Decrease) in expected cash flows based on actual cash flows and changes in cash flow assumptions			—			1,783			—			(380	)		—			(17,433	)		—			3,894
Net transfers from nonaccretable difference to accretable yield			—			11,917			—			19,076			—			58,682			—			14,681
Balance at end of period		$	280,830		$	120,408		$	55,837		$	85,838		$	358,666		$	122,715		$	68,075		$	131,370

Fair_Value

Fair Value	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value	'
	4. Fair Value
	The Financial Accounting Standards Board (FASB) defines fair value as the exchange price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The FASB’s guidance also established a fair value hierarchy that prioritizes the inputs to these valuation techniques used to measure fair value, giving preference to quoted prices in active markets for identical assets or liabilities (level 1) and the lowest priority to unobservable inputs such as a reporting entity’s own data (level 3). Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in markets that are not active, observable inputs other than quoted prices, such as interest rates and yield curves, and inputs that are derived principally from or corroborated by observable market data by correlation or other means.
	Fair Value of Assets and Liabilities Measured on a Recurring Basis
	The following tables present for each of the fair value hierarchy levels the Company’s assets and liabilities that are measured at fair value (in thousands) on a recurring basis in the consolidated balance sheets.
			September 30, 2014
			Level 1		Level 2		Total
	Assets
	Available for sale debt securities:
	U.S. Treasury and government agency securities		$	300,702	$	—	$	300,702
	Municipal obligations			—		18,767		18,767
	Corporate debt securities			3,500		—		3,500
	Mortgage-backed securities			—		1,241,223		1,241,223
	Collateralized mortgage obligations			—		88,558		88,558
	Equity securities			9,660		—		9,660
	Total available for sale securities			313,862		1,348,548		1,662,410
	Derivative assets (1)			—		16,012		16,012
	Total recurring fair value measurements - assets		$	313,862	$	1,364,560	$	1,678,422
	Liabilities
	Derivative liabilities (1)		$	—	$	16,440	$	16,440
	Total recurring fair value measurements - liabilities		$	—	$	16,440	$	16,440
	-1	For further disaggregation of derivative assets and liabilities, see Note 5 - Derivatives.
			December 31, 2013
			Level 1		Level 2		Total
	Assets
	Available for sale debt securities:
	U.S. Treasury and government agency securities		$	505	$	—	$	505
	Municipal obligations			—		35,961		35,961
	Corporate debt securities			3,500		—		3,500
	Mortgage-backed securities			—		1,276,958		1,276,958
	Collateralized mortgage obligations			—		94,125		94,125
	Equity securities			10,723		—		10,723
	Total available for sale securities			14,728		1,407,044		1,421,772
	Derivative assets (1)			—		15,579		15,579
	Total recurring fair value measurements - assets		$	14,728	$	1,422,623	$	1,437,351
	Liabilities
	Derivative liabilities (1)		$	—	$	15,006	$	15,006
	Total recurring fair value measurements - liabilities		$	—	$	15,006	$	15,006
	-1	For further disaggregation of derivative assets and liabilities, see Note 5 - Derivatives.
	Securities classified as level 1 within the valuation hierarchy include U.S. Treasury securities, obligations of U.S. Government-sponsored agencies, and certain other debt and equity securities. Level 2 classified securities include residential mortgage-backed securities and collateralized mortgage obligations that are issued or guaranteed by U.S. government agencies, and state and municipal bonds. The level 2 fair value measurements for investment securities are obtained quarterly from a third-party pricing service that uses industry-standard pricing models. Substantially all of the model inputs are observable in the marketplace or can be supported by observable data. The Company invests only in high quality securities of investment grade quality with a targeted duration, for the overall portfolio, generally between two and five. Company policies limit investments to securities having a rating of not less than “Baa” or its equivalent by a nationally recognized statistical rating agency. There were no transfers between valuation hierarchy levels during the periods shown.
	The fair value of derivative financial instruments, which are predominantly customer interest rate swaps, is obtained from a third-party pricing service that uses an industry-standard discounted cash flow model that relies on inputs, LIBOR swap curves and Overnight Index swap rate curves, observable in the marketplace. To comply with the accounting guidance, credit valuation adjustments are incorporated in the fair values to appropriately reflect nonperformance risk for both the Company and the counterparties. Although the Company has determined that the majority of the inputs used to value the derivative instruments fall within level 2 of the fair value hierarchy, the credit value adjustments utilize level 3 inputs, such as estimates of current credit spreads. The Company has determined that the impact of the credit valuation adjustments is not significant to the overall valuation of these derivatives. As a result, the Company has classified its derivative valuations in their entirety in level 2 of the fair value hierarchy. The Company’s policy is to measure counterparty credit risk quarterly for all derivative instruments, including those subject to master netting arrangements consistent with how market participants would price the net risk exposure at the measurement date.
	The Company also has certain derivative instruments associated with the Bank’s mortgage-banking activities. These derivative instruments include interest rate lock commitments on prospective residential mortgage loans and forward commitments to sell these loans to investors on a best efforts delivery basis. The fair value of these derivative instruments is measured using observable market prices for similar instruments and is classified as a level 2 measurement.
	Fair Value of Assets Measured on a Nonrecurring Basis
	Certain assets and liabilities are measured at fair value on a nonrecurring basis. Collateral-dependent impaired loans are level 2 assets measured at the fair value of the underlying collateral based on independent third-party appraisals that take into consideration market-based information such as recent sales activity for similar assets in the property’s market.
	Other real estate owned, including both foreclosed property and surplus banking property, are level 3 assets that are adjusted to fair value, less estimated selling costs, upon transfer to other real estate owned. Subsequently, other real estate owned is carried at the lower of carrying value or fair value less estimated selling costs. Fair values are determined by sales agreement or third-party appraisals as discounted for estimated selling costs, information from comparable sales, and marketability of the property.
	The following tables present the Company’s financial assets that are measured at fair value (in thousands) on a nonrecurring basis for each of the fair value hierarchy levels.
			September 30, 2014
			Level 1		Level 2		Level 3		Total
	Collateral-dependent impaired loans		$	—	$	34,482	$	—	$	34,482
	Other real estate owned			—		—		20,742		20,742
	Total nonrecurring fair value measurements		$	—	$	34,482	$	20,742	$	55,224
			December 31, 2013
			Level 1		Level 2		Level 3		Total
	Collateral-dependent impaired loans		$	—	$	24,392	$	—	$	24,392
	Other real estate owned			—		—		25,525		25,525
	Total nonrecurring fair value measurements		$	—	$	24,392	$	25,525	$	49,917
	Accounting guidance from the FASB requires the disclosure of estimated fair value information about certain on-and off-balance sheet financial instruments, including those financial instruments that are not measured and reported at fair value on a recurring basis. The significant methods and assumptions used by the Company to estimate the fair value of financial instruments are discussed below.
	Cash, Short-Term Investments and Federal Funds Sold - For these short-term instruments, the carrying amount is a reasonable estimate of fair value.
	Securities – The fair value measurement for securities available for sale was discussed earlier in the note. The same measurement techniques were applied to the valuation of securities held to maturity.
	Loans, Net - The fair value measurement for certain impaired loans was discussed earlier in the note. For the remaining portfolio, fair values were generally determined by discounting scheduled cash flows using discount rates determined with reference to current market rates at which loans with similar terms would be made to borrowers of similar credit quality.
	Loans Held for Sale – Residential mortgage loans originated for sale are classified as loans held for sale and carried at the lower of cost or market. These loans are generally sold within 90 days. For these short-term instruments, the carrying amounts are a reasonable estimate of fair values.
	Accrued Interest Receivable and Accrued Interest Payable – For these short-term instruments, the carrying amounts are a reasonable estimate of fair values.
	Deposits - The accounting guidance requires that the fair value of deposits with no stated maturity, such as noninterest-bearing demand deposits, interest-bearing checking and savings accounts, be assigned fair values equal to amounts payable upon demand (carrying amounts). The fair value of fixed-maturity certificates of deposit is estimated using the rates currently offered for deposits of similar remaining maturities.
	Securities Sold under Agreements to Repurchase, Federal Funds Purchased, and FHLB Borrowings - For these short-term liabilities, the carrying amount is a reasonable estimate of fair value.
Long-Term Debt - The fair value is estimated by discounting the future contractual cash flows using current market rates at which debt with similar terms could be obtained.
Derivative Financial Instruments – The fair value measurement for derivative financial instruments was discussed earlier in the note.
The following tables present the estimated fair values of the Company’s financial instruments by fair value hierarchy levels and the corresponding carrying amount at September 30, 2014 and December 31, 2013 (in thousands):
		September 30, 2014
								Total		Carrying
		Level 1		Level 2		Level 3		Fair Value		Amount
Financial assets:
Cash, interest-bearing bank deposits, and federal funds sold		$	803,917	$	—	$	—	$	803,917	$	803,917
Available for sale securities			313,862		1,348,548		—		1,662,410		1,662,410
Held to maturity securities			—		2,253,219		—		2,253,219		2,250,960
Loans, net			—		34,482		13,081,700		13,116,182		13,223,002
Loans held for sale			—		15,098		—		15,098		15,098
Accrued interest receivable			44,164		—		—		44,164		44,164
Derivative financial instruments			—		16,012		—		16,012		16,012
Financial liabilities:
Deposits		$	—	$	—	$	15,434,876	$	15,434,876	$	15,736,694
Federal funds purchased			7,625		—		—		7,625		7,625
Securities sold under agreements to repurchase			599,184		—		—		599,184		599,184
FHLB borrowings			565,000		—		—		565,000		565,000
Long-term debt			—		344,636		—		344,636		376,452
Accrued interest payable			5,663		—		—		5,663		5,663
Derivative financial instruments			—		16,440		—		16,440		16,440
		December 31, 2013
								Total		Carrying
		Level 1		Level 2		Level 3		Fair Value		Amount
Financial assets:
Cash, interest-bearing bank deposits, and federal funds sold		$	617,280	$	—	$	—	$	617,280	$	617,280
Available for sale securities			14,728		1,407,044		—		1,421,772		1,421,772
Held to maturity securities			100,316		2,476,268		—		2,576,584		2,611,352
Loans, net			—		24,392		12,023,330		12,047,722		12,191,191
Loans held for sale			—		24,515		—		24,515		24,515
Accrued interest receivable			42,977		—		—		42,977		42,977
Derivative financial instruments			—		15,579		—		15,579		15,579
Financial liabilities:
Deposits		$	—	$	—	$	15,352,024	$	15,352,024	$	15,360,516
Federal funds purchased			7,725		—		—		7,725		7,725
Securities sold under agreements to repurchase			650,235		—		—		650,235		650,235
Long-term debt			—		385,557		—		385,557		385,826
Accrued interest payable			4,353		—		—		4,353		4,353
Derivative financial instruments			—		15,006		—		15,006		15,006

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivatives	'
	5. Derivatives
	Risk Management Objective of Using Derivatives
	The Bank has entered into interest rate derivative agreements as a service to certain qualifying customers. The Bank manages a matched book with respect to these customer derivatives in order to minimize the net risk exposure resulting from such agreements. The Company enters into derivative financial instruments to manage risks related to differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments. The Bank also enters into risk participation agreements under which it may either sell or buy credit risk associated with a customer’s performance under certain interest rate derivative contracts related to loans in which participation interests have been sold to or purchased from other banks.
	Fair Values of Derivative Instruments on the Balance Sheet
	The table below presents the notional amounts and fair values (in thousands) of the Company’s derivative financial instruments as well as their classification on the consolidated balance sheets as of September 30, 2014 and December 31, 2013.
													Fair Values (1)
					Notional Amounts								Assets								Liabilities
			Type of		September				December				September				December				September				December
			Hedge		30, 2014				31, 2013				30, 2014				31, 2013				30, 2014				31, 2013
	Derivatives not designated as hedging instruments:
	Interest rate swaps (2)		N/A		$	753,382			$	650,667			$	14,585			$	14,147			$	14,974			$	13,777
	Risk participation agreements		N/A			80,989				19,736				105				2				156				2
	Forward commitments to sell residential mortgage loans		N/A			40,873				45,910				56				326				640				115
	Interest rate-lock commitments on residential mortgage loans		N/A			28,025				25,956				595				56				27				107
	Foreign exchange forward contracts		N/A			37,127				21,299				671				1,048				643				1,005
					$	940,396			$	763,568			$	16,012			$	15,579			$	16,440			$	15,006
	-1	Derivative assets and liabilities are reported with other assets or other liabilities, respectively, in the consolidated balance sheets.
	-2	The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.
	Derivatives Not Designated as Hedges
	Customer interest rate derivatives
	The Bank enters into interest rate derivative agreements, primarily rate swaps, with commercial banking customers to facilitate their risk management strategies. The Bank simultaneously enters into offsetting agreements with unrelated financial institutions, thereby mitigating its net risk exposure resulting from such transactions. Because the interest rate derivatives associated with this program do not meet hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings as part of other income.
	Risk participation agreements
	The Bank enters into risk participation agreements under which it may either assume or sell credit risk associated with a borrower’s performance under certain interest rate derivative contracts. In those instances where the Bank has assumed credit risk, it is not a direct counterparty to the derivative contract with the borrower and has entered into the risk participation agreement because it is a party to the related loan agreement with the borrower. In those instances in which the Bank has sold credit risk, it is the sole counterparty to the derivative contract with the borrower and has entered into the risk participation agreement because other banks participate in the related loan agreement. The Bank manages its credit risk under risk participation agreements by monitoring the creditworthiness of the borrower, based on its normal credit review process.
	Mortgage banking derivatives
	The Bank also enters into certain derivative agreements as part of its mortgage banking activities. These agreements include interest rate lock commitments on prospective residential mortgage loans and forward commitments to sell these loans to investors on a best efforts delivery basis.
	Customer foreign exchange forward contract derivatives
	The Bank enters into foreign exchange forward derivative agreements, primarily forward currency contracts, with commercial banking customers to facilitate its risk management strategies. The Bank manages its risk exposure from such transactions by entering into offsetting agreements with unrelated financial institutions. Because the foreign exchange forward contract derivatives associated with this program do not meet hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings as part of other income.
	Effect of Derivative Instruments on the Income Statement
	The effect of the Company’s derivative financial instruments on the income statement was immaterial for the three-month and nine-month periods ended September 30, 2014 and 2013.
	Credit risk-related Contingent Features
	Certain of the Bank’s derivative instruments contain provisions allowing the financial institution counterparty to terminate the contracts in certain circumstances, such as the downgrade of the Bank’s credit ratings below specified levels, a default by the Bank on its indebtedness, or the failure of the Bank to maintain specified minimum regulatory capital ratios or its regulatory status as a well-capitalized institution. These derivative agreements also contain provisions regarding the posting of collateral by each party. As of September 30, 2014, the aggregate fair value of derivative instruments with credit risk-related contingent features that were in a net liability position was $6 million, for which the Bank had posted collateral of $17 million.
	Offsetting Assets and Liabilities
	Offsetting information in regards to derivative assets and liabilities subject to master netting agreements at September 30, 2014 and December 31, 2013 is presented in the following tables (in thousands):
							Gross				Net Amounts				Gross
							Amounts				Presented in				Amounts
							Offset in								Not Offset
															in the
															Statement
															of Financial
	Description		Gross				the				the				Financial				Cash				Net
			Amounts				Statement of				Statement				Instruments				Collateral				Amount
			Recognized				Financial				of Financial
							Position				Position
	As of September 30, 2014
	Derivative Assets		$	14,690			$	—			$	14,690			$	2,206			$	—			$	12,484
	Total		$	14,690			$	—			$	14,690			$	2,206			$	—			$	12,484
	Derivative Liabilities		$	15,129			$	—			$	15,129			$	2,206			$	16,767			$	(3,844	)
	Total		$	15,129			$	—			$	15,129			$	2,206			$	16,767			$	(3,844	)
	As of December 31, 2013
	Derivative Assets		$	14,149			$	—			$	14,149			$	3,462			$	—			$	10,687
	Total		$	14,149			$	—			$	14,149			$	3,462			$	—			$	10,687
	Derivative Liabilities		$	13,779			$	—			$	13,779			$	3,462			$	7,406			$	2,911
	Total		$	13,779			$	—			$	13,779			$	3,462			$	7,406			$	2,911

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Stockholders' Equity	'
	6. Stockholders’ Equity
	Stock Repurchase Program
	On July 16, 2014, the Company’s board of directors approved a stock repurchase plan that authorizes the repurchase of up to 5%, or approximately 4 million shares, of its currently outstanding common stock. The approved plan allows the Company to repurchase its common shares either in the open market in compliance with Rule 10b-18 promulgated under the Securities Exchange Act of 1934, as amended, or in privately negotiated transactions with non-affiliated sellers or as otherwise determined by the Company in one or more transactions, from time to time until December 31, 2015. Under this plan, we have repurchased 305,263 shares of our common stock at an average price of $32.65 per share.
	The Company’s board of directors approved a stock repurchase program on April 30, 2013 that authorized the repurchase of up to 5% of the Company’s outstanding common stock. On May 8, 2013 Hancock entered into an accelerated share repurchase (ASR) transaction with Morgan Stanley & Co. LLC (Morgan Stanley). In the ASR transaction, the Company paid $115 million to Morgan Stanley and received from them approximately 3 million shares of Hancock common stock, representing approximately 76% of the estimated total number of shares to be repurchased. On May 5, 2014, final settlement of the ASR agreement occurred at which time the Company received approximately 0.6 million shares from Morgan Stanley. The number of shares delivered to the Company in this
	ASR transaction was based generally on the volume-weighted average price per share of the Hancock common stock during the term of the ASR agreement less a specified discount and on the amount paid at inception to Morgan Stanley, subject to certain adjustments in accordance with the terms of the ASR agreement. The ASR transaction was treated as two separate transactions: (i) the acquisition of treasury shares on the dates the shares were received; and (ii) a forward contract indexed to the Company’s common stock that was classified as equity. The 2013 program was superseded by the 2014 program.
	Accumulated Other Comprehensive Income (Loss)
	Accumulated other comprehensive income (loss) (AOCI) is reported as a component of stockholders’ equity. AOCI can include, among other items, unrealized holding gains and losses on securities available for sale (AFS), gains and losses associated with pension or other post retirement benefits that are not recognized immediately as a component of net periodic benefit cost, and gains and losses on derivative instruments that are designated as, and qualify as, cash flow hedges. Net unrealized gains/losses on AFS securities reclassified as securities held to maturity (HTM) also continue to be reported as a component of AOCI and will be amortized over the estimated remaining life of the securities as an adjustment to interest income. The components of AOCI are reported net of related tax effects.
	The components of AOCI and changes in those components are presented in the following table (in thousands).
			Available			HTM Securities						Loss on
			for Sale			Transferred			Employee			Effective Cash
			Securities			from AFS			Benefit Plans			Flow Hedges			Total
	Balance, January 1, 2013		$	38,854		$	19,090		$	(80,688	)	$	(181	)	$	(22,925	)
	Other comprehensive income before income taxes:
	Net change in unrealized (loss) gain			(96,070	)		—			—			(4	)		(96,074	)
	Transfer of net unrealized gain from AFS to HTM, net of cumulative tax effect			36,208			(36,208	)		—			—			—
	Reclassification of net losses realized and included in earnings			—			—			5,534			301			5,835
	Amortization of unrealized net gain on securities transferred to HTM			—			(7,099	)		—			—			(7,099	)
	Income tax (benefit) expense			(35,115	)		(2,563	)		2,070			116			(35,492	)
	Balance, September 30, 2013		$	14,107		$	(21,654	)	$	(77,224	)	$	—		$	(84,771	)
	Balance, January 1, 2014		$	8,263		$	(21,189	)	$	(22,453	)	$	—		$	(35,379	)
	Other comprehensive income before income taxes:
	Net change in unrealized gain			9,119			—			—			—			9,119
	Reclassification of net losses realized and included in earnings			—			—			2,195			—			2,195
	Amortization of unrealized net gain on securities transferred to HTM			—			2,463			—			—			2,463
	Income tax expense			3,309			879			903			—			5,091
	Balance, September 30, 2014		$	14,073		$	(19,605	)	$	(21,161	)	$	—		$	(26,693	)
	The following table shows the line item affected by amounts reclassified from accumulated other comprehensive income:
	Amount reclassified from AOCI		Nine Months Ended						Increase (decrease)
			September 30,						in affected line item
	(in thousands)		2014			2013			on the income statement
	Amortization/accretion of unrealized net gain/(loss) on securities transferred to HTM		$	2,463		$	(7,099	)	Interest income
	Tax effect			879			(2,563	)	Income taxes
	Net of tax			1,584			(4,536	)	Net income
	Amortization of defined benefit pension and post-retirement items		$	293		$	5,534		(a) Employee benefits expense
	Tax effect			103			2,070		Income taxes
	Net of tax			190			3,464		Net income
	Gains and losses on cash flow hedges		$	—		$	301		Interest expense
	Tax effect			—			105		Income taxes
	Net of tax			—			196		Net income
	Total reclassifications, net of tax		$	1,774		$	(876	)	Net income
	(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 9 for additional details).

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	7. Earnings Per Share
	Hancock calculates earnings per share using the two-class method. The two-class method allocates net income to each class of common stock and participating security according to common dividends declared and participation rights in undistributed earnings. Participating securities consist of unvested stock-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents.
	A summary of the information used in the computation of earnings per common share follows (in thousands, except per share amounts):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2014		2013		2014		2013
	Numerator:
	Net income to common shareholders	$	46,553	$	33,202	$	135,630	$	128,640
	Net income allocated to participating securities - basic and diluted		883		616		2,783		2,398
	Net income allocated to common shareholders - basic and diluted	$	45,670	$	32,586	$	132,847	$	126,242
	Denominator:
	Weighted average common shares - basic		81,721		82,091		81,965		83,404
	Dilutive potential common shares		221		114		239		92
	Weighted average common shares - diluted		81,942		82,205		82,204		83,496
	Earnings per common share:
	Basic	$	0.56	$	0.4	$	1.62	$	1.51
	Diluted	$	0.56	$	0.4	$	1.62	$	1.51
	Potential common shares consist of employee and director stock options. These potential common shares do not enter into the calculation of diluted earnings per share if the impact would be anti-dilutive, i.e., increase earnings per share or reduce a loss per share. Weighted average anti-dilutive potential common shares totaled 569,404 and 639,486 respectively for the three and nine months ended September 30, 2014 and 721,863 and 1,076,894, respectively, for the three and nine months ended September 30, 2013.

ShareBased_Payment_Arrangement

Share-Based Payment Arrangements	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Payment Arrangements	'
	8. Share-Based Payment Arrangements
	Hancock maintains incentive compensation plans that provide for awards of share-based compensation to employees and directors. These plans have been approved by the Company’s shareholders. Detailed descriptions of these plans were included in Note 13 to the consolidated financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	A summary of option activity for the nine months ended September 30, 2014 is presented below:
							Weighted
							Average
					Weighted		Remaining
					Average		Contractual		Aggregate
		Number of			Exercise		Term		Intrinsic
	Options	Shares			Price		(Years)		Value ($000)
	Outstanding at January 1, 2014		1,332,656		$	38.85
	Exercised		(32,618	)		29.51
	Cancelled/Forfeited		(16,549	)		38.26
	Expired		(113,447	)		63.41
	Outstanding at September 30, 2014		1,170,042		$	36.74		4.4	$	799
	Exercisable at September 30, 2014		885,673		$	38.55		3.6	$	373
	The total intrinsic value of options exercised during the nine months ended September 30, 2014 and 2013 was $0.2 million and $0.1 million, respectively.
	A summary of the status of the Company’s nonvested restricted and performance shares as of September 30, 2014 and changes during the nine months ended September 30, 2014, is presented below. These restricted and performance shares are subject to service requirements.
					Weighted
					Average
		Number of			Grant Date
		Shares			Fair Value
	Nonvested at January 1, 2014		1,981,820		$	31.75
	Granted		120,396			36.23
	Vested		(272,788	)		32
	Forfeited		(85,873	)		31.69
	Nonvested at September 30, 2014		1,743,555		$	32.02
	As of September 30, 2014, there were $31.7 million of total unrecognized compensation expense related to nonvested restricted and performance shares expected to vest. This compensation is expected to be recognized in expense over a weighted average period of 3.1 years. The total fair value of shares which vested during the nine months ended September 30, 2014 and 2013 was $10 million and $1 million, respectively.
	During the nine months ended September 30, 2014, the Company granted 69,857 performance shares with a grant date fair value of $38.14 per share to key members of executive and senior management. The number of 2014 performance shares that ultimately vest at the end of the three-year required service period, if any, will be based on the relative rank of Hancock’s three-year total shareholder return (TSR) among the TSRs of a peer group of fifty regional banks. The maximum number of performance shares that could vest is 200% of the target award. The fair value of the performance awards at the grant date was determined using a Monte Carlo simulation method. Compensation expense for these performance shares will be recognized on a straight-line basis over the service period.

Retirement_Plans

Retirement Plans	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Retirement Plans	'
	9. Retirement Plans
	The Company has a qualified defined benefit pension plan covering all eligible employees. Eligibility is based on minimum age- and service-related requirements as well as job classification. Accrued benefits under a nonqualified plan covering certain legacy Whitney employees were frozen as of December 31, 2012 and no future benefits will be accrued under this plan.
	The Company also sponsors defined benefit postretirement plans for both legacy Hancock and legacy Whitney employees that provide health care and life insurance benefits. Benefits under the Hancock plan are not available to employees hired on or after January 1, 2000. Benefits under the Whitney plan are restricted to retirees who were already receiving benefits at the time of plan amendments in 2007 or active participants who were eligible to receive benefits as of December 31, 2007.
	The following table shows the components of net periodic benefits cost included in expense for the plans for the periods indicated (in thousands).
		Three Months Ended September 30,
		2014			2013			2014		2013
								Other Post-
		Pension benefits						retirement Benefits
	Service cost	$	3,230		$	3,969		$	31	$	52
	Interest cost		4,812			4,151			285		327
	Expected return on plan assets		(8,056	)		(6,982	)		—		—
	Amortization of net loss		7			1,605			91		459
	Net periodic benefit cost	$	(7	)	$	2,743		$	407	$	838
		Nine Months Ended September 30,
		2014			2013			2014		2013
								Other Post-
		Pension benefits						retirement Benefits
	Service cost	$	9,690		$	11,905		$	94	$	162
	Interest cost		14,438			12,457			855		987
	Expected return on plan assets		(24,167	)		(20,946	)		—		—
	Amortization of net loss		20			4,813			273		1,320
	Net periodic benefit cost	$	(19	)	$	8,229		$	1,222	$	2,469
	Based on currently available information, Hancock does not anticipate making a contribution to the pension plan during 2014.
	The Company also provides a defined contribution retirement benefit plan (401(k) plan). Under the plan, the Company matches 100% of the first 1% of compensation saved by a participant, and 50% of the next 5% of compensation saved.

Other_Noninterest_Income

Other Noninterest Income	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Other Noninterest Income	'
	10. Other Noninterest Income
	Components of other noninterest income are as follows:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014			2013		2014		2013
	(In thousands)
	Income from bank owned life insurance	$	2,377		$	2,656	$	7,048	$	8,764
	Credit related fees		2,822			2,995		8,388		5,969
	Income from derivatives		191			1,257		1,431		3,296
	Net (loss) gain on sale of assets		(56	)		801		1,409		1,277
	Safety deposit box income		448			467		1,404		1,480
	Other miscellaneous		1,950			1,940		7,091		6,453
	Total other noninterest income	$	7,732		$	10,116	$	26,771	$	27,239

Other_Noninterest_Expense

Other Noninterest Expense	9 Months Ended
	Sep. 30, 2014
Text Block [Abstract]	'
Other Noninterest Expense	'
	11. Other Noninterest Expense
	Components of other noninterest expense are as follows:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
	(In thousands)	2014		2013		2014		2013
	Advertising	$	2,457	$	2,858	$	6,395	$	7,216
	Ad valorem and franchise taxes		3,098		2,809		8,397		7,193
	Printing and supplies		1,189		1,143		3,467		3,963
	Insurance expense		944		887		3,002		3,018
	Travel expense		1,009		1,074		2,966		3,475
	Entertainment and contributions		1,396		969		4,337		3,960
	Tax credit investment amortization		2,220		4,880		6,590		7,553
	Other miscellaneous		6,821		19,851		25,105		32,504
	Total other noninterest expense	$	19,134	$	34,471	$	60,259	$	68,882
	Other miscellaneous expense for the nine months ended September 30, 2014 as shown in the table above includes nonoperating items totaling $1.1 million in the third quarter of 2014, $7.3 million in the second quarter of 2014 and $12.6 million in the third quarter of 2013. These items are further discussed below:
	FDIC Settlement
	During the second quarter of 2014, the Company recorded a $10.3 million expense for the settlement of an assessment by the FDIC related to its targeted review of certain previously paid loss claim reimbursement amounts. The assessment demanded repayment of these amounts due to the FDIC’s disagreement with the manner in which certain assets were administered and losses were calculated. During the third quarter, the settlement was paid and the FDIC began payment of claims.
	Sale of Insurance Business
	In April 2014, the Company sold its property and casualty and group benefits insurance intermediary business. The lines of business being divested represent approximately half of the Company’s 2013 insurance commissions and fees. A gain of $9.4 million was recorded on the sale based on a $15.5 million sales price less the related tangible and intangible assets.
	Branch Closures
	During the second and third quarters of 2014, the Company recorded $3.5 million and $1.1 million, respectively, in write-downs related to the 2014 closure of 15 branch locations in Mississippi, Florida and Louisiana as part of its ongoing branch rationalization process. Of the $3.5 million, $2.9 million is included in other miscellaneous expense.
	Reverse Repurchase Obligations Early Termination Fee
	During the second quarter of 2014, the Company recorded $3.5 million in fees related to the early termination of reverse repurchase obligations.

New_Accounting_Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2014
Accounting Changes and Error Corrections [Abstract]	'
New Accounting Pronouncements	'
	12. New Accounting Pronouncements
	In June 2014, the Financial Accounting Standards Board (FASB) issued an Accounting Standard Update (ASU) that requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. For all entities, the amendments in this ASU are effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Earlier adoption is permitted. The effective date is the same for both public business entities and all other entities. The adoption of this guidance is not expected to have a material impact on the Company’s financial condition or results of operations.
	In June 2014, the FASB issued an ASU regarding repurchase-to-maturity transactions, repurchase financings, and disclosures. Under the new standard, repurchase-to-maturity transactions will be reported as secured borrowings, and transferors will no longer apply the current “linked” accounting model to repurchase agreements executed contemporaneously with the initial transfer of the underlying financial asset with the same counterparty. Public business entities are generally required to apply the accounting changes and comply with the enhanced disclosure requirements for periods beginning after December 15, 2014 and interim periods beginning after March 15, 2015. A public business entity may not early adopt the standard’s provisions. The adoption of this guidance is not expected to have a material impact on the Company’s financial condition or results of operations.
	In May 2014, the FASB issued an ASU regarding revenue from contracts with customers affecting any entity that enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards. The core principle of this standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard will be effective for the Company for periods beginning after December 15, 2016. The Company is currently assessing this pronouncement and adoption of this guidance is not expected to have a material impact on the Company’s financial condition or results of operations.
	In April 2014, the FASB issued a new standard changing the threshold for reporting discontinued operations and adding new disclosures for disposals. The new guidance defines a discontinued operation as a component or group of components that is disposed of or is classified as held for sale and “represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results.” New disclosure and presentation requirements apply to discontinued operations and to disposals of individually significant components that do not qualify as discontinued operations. The guidance applies prospectively to new disposals of components and new classifications as held for sale beginning in 2015 for most entities, with early adoption allowed. The Company early adopted this pronouncement in the second quarter of 2014. The adoption of this guidance did not have a material impact on the Company’s financial condition or results of operations.
	In January 2014, the FASB issued an ASU on reclassification of residential real estate collateralized consumer mortgage loans upon foreclosure. The new ASU clarifies when an in substance repossession or foreclosure occurs – that is, when a creditor should be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that the loan receivable should be derecognized and the real estate property recognized. The new ASU requires a creditor to reclassify a collateralized consumer mortgage loan to real estate property upon obtaining legal title to the real estate collateral, or the borrower voluntarily conveying all interest in the real estate property to the lender to satisfy the loan through a deed in lieu of foreclosure or similar legal agreement. The ASU is effective for interim and annual reporting periods beginning after December 15, 2014. The adoption of this guidance is not expected to have a material impact on the Company’s financial condition or results of operations.

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	1. Basis of Presentation
	The consolidated financial statements include the accounts of Hancock Holding Company and all other entities in which it has a controlling interest (the “Company”). The financial statements include all adjustments that are, in the opinion of management, necessary to present fairly the Company’s financial condition, results of operations, changes in stockholders’ equity and cash flows for the interim periods presented. Some financial information and disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the U.S. (U.S. GAAP) have been condensed or omitted in this Form 10-Q pursuant to Securities and Exchange Commission rules and regulations. These financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013. Financial information reported in these financial statements is not necessarily indicative of the Company’s financial condition, results of operations, or cash flows for any other interim or annual period.
Use of Estimates	'
	Use of Estimates
	The accounting principles the Company follows and the methods for applying these principles conform with U.S. GAAP and with those generally practiced within the banking industry. These accounting principles require management to make estimates and assumptions about future events that affect the amounts reported in the consolidated financial statements and the accompanying notes. Actual results could differ from those estimates.
Income Taxes	'
	Income Taxes
	Income taxes are accounted for using the asset and liability method. Current tax liabilities or assets are recognized for the estimated income taxes payable or refundable on tax returns to be filed with respect to the current year. Deferred tax assets and liabilities are based on temporary differences between the financial statement carrying amounts and the tax bases of the Company’s assets and liabilities. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be realized or settled. Valuation allowances are established against deferred tax assets if, based on all available evidence, it is more likely than not that some or all of the assets will not be realized. The benefit of a position taken or expected to be taken in a tax return is recognized when it is more likely than not that the position will be sustained on its technical merits.
	The Company invests in projects that yield tax credits issued under the Qualified Zone Academy Bonds (QZAB), Qualified School Construction Bonds (QSCB), Federal and State New Market Tax Credit (NMTC), and Low-Income Housing Tax Credit (LIHTC) programs. Returns on these investments are generated through the receipt of federal and state tax credits. The tax credits are recorded as a reduction to the income tax provision in the year that they are earned. Tax credits from QZAB and QSCB bonds are generally earned over the life of the bonds in lieu of interest income. Credits on Federal NMTC investments are earned over the seven-year compliance period beginning with the year of investment. Credits on State NMTC investments are generally earned over a three- to five- year period depending upon the specific state program. Tax Credits for Low-Income Housing investments are earned over a ten-year period beginning with the year in which rental activity begins. These tax credits, if not used in the tax return for the year when the credits are first available for use, can be carried forward for 20 years. For those investments where the return of the principal is not expected, the equity investment is amortized over the life of the tax compliance period as a component of noninterest expense.
Reportable Segment Disclosures	'
	Reportable Segment Disclosures
	Accounting standards require that information be reported about a company’s operating segments using a “management approach.” Reportable segments are identified in these standards as those revenue-producing components for which separate financial information is produced internally and which are subject to evaluation by the chief operating decision maker in deciding how to allocate resources to segments. On March 31, 2014, the Company combined its two state bank charters into one charter. Due to the charter change and consistent with its stated strategy that is focused on providing a consistent package of community banking products and services across all markets, the Company has identified its overall banking operations as its only reportable segment. Because the overall banking operations comprise substantially all of the consolidated operations, no separate segment disclosures are presented.
	There were no other material changes or developments with respect to methodologies that the Company uses when applying what management believes are critical accounting policies and developing critical accounting estimates as disclosed in our Annual Report on Form 10-K for the year ended December 31, 2013.

Securities_Tables

Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Amortized Cost and Fair Value of Available for Sale Securities	'
	The amortized cost and fair value of securities classified as available for sale and held to maturity follow (in thousands):
	Securities Available for Sale
		September 30, 2014								December 31, 2013
				Gross		Gross						Gross		Gross
		Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	US Treasury and government agency securities	$	300,257	$	446	$	1	$	300,702	$	504	$	2	$	1	$	505
	Municipal obligations		18,495		272		—		18,767		35,809		177		25		35,961
	Mortgage-backed securities		1,218,982		27,566		5,325		1,241,223		1,262,633		24,402		10,077		1,276,958
	CMOs		90,281		—		1,723		88,558		96,369		—		2,244		94,125
	Corporate debt securities		3,500		—		—		3,500		3,500		—		—		3,500
	Equity securities		8,784		877		1		9,660		9,965		785		27		10,723
		$	1,640,299	$	29,161	$	7,050	$	1,662,410	$	1,408,780	$	25,366	$	12,374	$	1,421,772
Amortized Cost and Fair Value of Held to Maturity Securities	'
	Securities Held to Maturity
		September 30, 2014								December 31, 2013
				Gross		Gross						Gross		Gross
		Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	US Treasury and government agency securities	$	—	$	—	$	—	$	—	$	100,000	$	316	$	—	$	100,316
	Municipal obligations		183,379		2,911		1,709		184,581		193,189		919		6,436		187,672
	Mortgage-backed securities		926,163		12,426		1,258		937,331		1,003,327		296		4,671		998,952
	CMOs		1,141,418		5,888		15,999		1,131,307		1,314,836		1,062		26,254		1,289,644
		$	2,250,960	$	21,225	$	18,966	$	2,253,219	$	2,611,352	$	2,593	$	37,361	$	2,576,584
Available for Sale Securities Unrealized Losses	'
	The details for securities classified as available for sale with unrealized losses for the periods indicated follow (in thousands):
	September 30, 2014	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	US Treasury and government agency securities	$	163	$	1	$	25	$	—	$	188	$	1
	Municipal obligations		—		—		—		—		—		—
	Mortgage-backed securities		64,485		514		125,977		4,811		190,462		5,325
	CMOs		48,604		324		39,954		1,399		88,558		1,723
	Equity securities		—		—		3		1		3		1
		$	113,252	$	839	$	165,959	$	6,211	$	279,211	$	7,050
	December 31, 2013	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	US Treasury and government agency securities	$	205	$	1	$	—	$	—	$	205	$	1
	Municipal obligations		7,975		25		—		—		7,975		25
	Mortgage-backed securities		376,350		7,164		49,061		2,913		425,411		10,077
	CMOs		94,125		2,244		—		—		94,125		2,244
	Equity securities		3,282		26		3		1		3,285		27
		$	481,937	$	9,460	$	49,064	$	2,914	$	531,001	$	12,374
Held to Maturity with Unrealized Losses	'
	The details for securities classified as held to maturity with unrealized losses for the periods indicated follow (in thousands):
	Held to maturity
	September 30, 2014	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	Municipal obligations	$	2,812	$	54	$	55,817	$	1,655	$	58,629	$	1,709
	Mortgage-backed securities		—		—		128,802		1,258		128,802		1,258
	CMOs		68,903		350		557,747		15,649		626,650		15,999
		$	71,715	$	404	$	742,366	$	18,562	$	814,081	$	18,966
	December 31, 2013	Losses < 12 months				Losses 12 months or >				Total
				Gross				Gross				Gross
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	Municipal obligations	$	131,499	$	6,311	$	2,878	$	125	$	134,377	$	6,436
	Mortgage-backed securities		950,288		4,671		—		—		950,288		4,671
	CMOs		947,061		25,088		175,633		1,166		1,122,694		26,254
		$	2,028,848	$	36,070	$	178,511	$	1,291	$	2,207,359	$	37,361
Available for Sale Securities [Member]	'
Amortized Cost and Fair Value of Available for Sale Securities by Final Contractual Maturity	'
	The following table presents the amortized cost and fair value of debt securities at September 30, 2014 by contractual maturity (in thousands). Actual maturities will differ from contractual maturities because of rights to call or repay obligations with or without penalties and scheduled and unscheduled principal payments on mortgage-backed securities and CMOs.
		Amortized		Fair
		Cost		Value
	Debt Securities Available for Sale
	Due in one year or less	$	307,762	$	308,233
	Due after one year through five years		153,025		152,887
	Due after five years through ten years		218,513		225,794
	Due after ten years		952,215		965,836
	Total available for sale debt securities	$	1,631,515	$	1,652,750
Held to Maturity Securities Transferred from AFS [Member]	'
Amortized Cost and Fair Value of Available for Sale Securities by Final Contractual Maturity	'
		Amortized		Fair
		Cost		Value
	Debt Securities Held to Maturity
	Due in one year or less	$	5,302	$	5,317
	Due after one year through five years		638,277		626,915
	Due after five years through ten years		100,941		99,697
	Due after ten years		1,506,440		1,521,290
	Total held to maturity securities	$	2,250,960	$	2,253,219

Loans_and_Allowance_for_Loan_L1

Loans and Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2014
Loans, Net of Unearned Income	'
	Loans, net of unearned income, consisted of the following:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Originated loans:
	Commercial non-real estate	$	4,806,740		$	4,113,837
	Construction and land development		974,442			752,381
	Commercial real estate		2,245,855			2,022,528
	Residential mortgages		1,635,462			1,196,256
	Consumer		1,623,069			1,409,130
	Total originated loans	$	11,285,568		$	9,494,132
	Acquired loans:
	Commercial non-real estate	$	769,226		$	926,997
	Construction and land development		110,294			142,931
	Commercial real estate		813,429			967,148
	Residential mortgages		37,739			315,340
	Consumer		51,488			119,603
	Total acquired loans	$	1,782,176		$	2,472,019
	Covered loans:
	Commercial non-real estate	$	11,171		$	23,390
	Construction and land development		11,166			20,229
	Commercial real estate		41,550			53,165
	Residential mortgages		185,289			209,018
	Consumer		31,654			52,864
	Total covered loans	$	280,830		$	358,666
	Total loans:
	Commercial non-real estate	$	5,587,137		$	5,064,224
	Construction and land development		1,095,902			915,541
	Commercial real estate		3,100,834			3,042,841
	Residential mortgages		1,858,490			1,720,614
	Consumer		1,706,211			1,581,597
	Total loans	$	13,348,574		$	12,324,817
Schedule of Activity in Loss Share Receivable	'
	The following schedule shows activity in the loss share receivable for the nine months ended September 30, 2014 and 2013 (in thousands):
		Nine Months Ended
		September 30,			September 30,
		2014			2013
	Balance, January 1	$	113,834		$	177,844
	Amortization		(9,989	)		(590	)
	Charge-offs, write-downs and other losses (recoveries)		(793	)		(190	)
	External expenses qualifying under loss share agreement		3,325			7,918
	Changes due to changes in cash flow projections		(14,569	)		—
	Settlement of disallowed loss claims		(10,268	)		—
	Net payments to (from) FDIC		366			(60,886	)
	Ending balance	$	81,906		$	124,096
Allowance for Loan Losses by Portfolio Segment and Related Recorded Investment in Loans	'
	The following schedule shows activity in the allowance for loan losses by portfolio segment for the nine months ended September 30, 2014 and 2013 as well as the corresponding recorded investment in loans at the end of each period.
		Commercial			Construction			Commercial			Residential			Consumer			Total
		non-real			and land			real estate			mortgages
		estate			development
	(In thousands)	Nine Months Ended September 30, 2014
	Originated loans
	Allowance for loan losses:
	Beginning balance	$	33,091		$	6,180		$	20,649		$	6,892		$	12,073		$	78,885
	Charge-offs		(4,690	)		(2,615	)		(2,255	)		(1,793	)		(11,920	)		(23,273	)
	Recoveries		2,118			1,220			1,231			501			3,722			8,792
	Net provision for loan losses		3,929			2,151			(3,231	)		3,647			10,921			17,417
	Ending balance	$	34,448		$	6,936		$	16,394		$	9,247		$	14,796		$	81,821
	Ending balance:
	Individually evaluated for impairment	$	24		$	250		$	98		$	382		$	—		$	754
	Collectively evaluated for impairment		34,424			6,686			16,296			8,865			14,796			81,067
	Loans:
	Ending balance:	$	4,806,740		$	974,442		$	2,245,855		$	1,635,462		$	1,623,069		$	11,285,568
	Individually evaluated for impairment		5,582			6,617			14,486			2,712			—			29,397
	Collectively evaluated for impairment		4,801,158			967,825			2,231,369			1,632,750			1,623,069			11,256,171
	Acquired loans
	Allowance for loan losses:
	Beginning balance	$	1,603		$	10		$	34		$	—		$	—		$	1,647
	Charge-offs		—			—			—			—			—			—
	Recoveries		—			—			—			—			—			—
	Net provision for loan losses		5,800			1,436			57			(4	)		182			7,471
	Ending balance	$	7,403		$	1,446		$	91		$	(4	)	$	182		$	9,118
	Ending balance:
	Individually evaluated for impairment	$	92		$	426		$	46		$	—		$	—		$	564
	Amounts related to acquired-impaired loans		—			—			—			—			—			—
	Collectively evaluated for impairment		7,311			1,020			45			(4	)		182			8,554
	Loans:
	Ending balance:	$	769,226		$	110,294		$	813,429		$	37,739		$	51,488		$	1,782,176
	Individually evaluated for impairment		931			2,284			458			28			—			3,701
	Acquired-impaired loans		4,064			19,200			27,392			5,038			143			55,837
	Collectively evaluated for impairment		764,231			88,810			785,579			32,673			51,345			1,722,638
		Commercial			Construction			Commercial			Residential			Consumer			Total
		non-real			and land			real estate			mortgages
		estate			development
	(In thousands)	Nine Months Ended September 30, 2014
	Covered loans
	Allowance for loan losses:
	Beginning balance	$	2,323		$	2,655		$	10,929		$	27,989		$	9,198		$	53,094
	Charge-offs		(176	)		(350	)		(4,480	)		(677	)		(1,192	)		(6,875	)
	Recoveries		467			1,504			1,408			1			370			3,750
	Net provision for loan losses		(79	)		(138	)		(125	)		(257	)		(167	)		(766	)
	Decrease in FDIC loss share receivable		(1,507	)		(2,404	)		(2,418	)		(4,873	)		(3,368	)		(14,570	)
	Ending balance	$	1,028		$	1,267		$	5,314		$	22,183		$	4,841		$	34,633
	Ending balance:
	Individually evaluated for impairment	$	—		$	—		$	—		$	—		$	—		$	—
	Amounts related to acquired-impaired loans		1,028			1,267			5,314			22,183			4,841			34,633
	Collectively evaluated for impairment		—			—			—			—			—			—
	Loans:
	Ending balance:	$	11,171		$	11,166		$	41,550		$	185,289		$	31,654		$	280,830
	Individually evaluated for impairment		—			—			—			—			—			—
	Acquired-impaired loans		11,171			11,166			41,550			185,289			31,654			280,830
	Collectively evaluated for impairment		—			—			—			—			—			—
	Total loans
	Allowance for loan losses:
	Beginning balance	$	37,017		$	8,845		$	31,612		$	34,881		$	21,271		$	133,626
	Charge-offs		(4,866	)		(2,965	)		(6,735	)		(2,470	)		(13,112	)		(30,148	)
	Recoveries		2,585			2,724			2,639			502			4,092			12,542
	Net provision for loan losses		9,650			3,449			(3,299	)		3,386			10,936			24,122
	Decrease in FDIC loss share receivable		(1,507	)		(2,404	)		(2,418	)		(4,873	)		(3,368	)		(14,570	)
Ending balance	$	42,879		$	9,649		$	21,799		$	31,426		$	19,819		$	125,572
Ending balance:
Individually evaluated for impairment	$	116		$	676		$	144		$	382		$	—		$	1,318
Amounts related to acquired-impaired loans		1,028			1,267			5,314			22,183			4,841			34,633
Collectively evaluated for impairment		41,735			7,706			16,341			8,861			14,978			89,621
Loans:
Ending balance:	$	5,587,137		$	1,095,902		$	3,100,834		$	1,858,490		$	1,706,211		$	13,348,574
Individually evaluated for impairment		6,513			8,901			14,944			2,740			—			33,098
Acquired-impaired loans		15,235			30,366			68,942			190,327			31,797			336,667
Collectively evaluated for impairment		5,565,389			1,056,635			3,016,948			1,665,423			1,674,414			12,978,809
	Commercial			Construction			Commercial			Residential			Consumer			Total
	non-real			and land			real estate			mortgages
	estate			development
(In thousands)	Nine Months Ended September 30, 2013
Originated loans
Allowance for loan losses:
Beginning balance	$	20,775		$	11,415		$	26,959		$	6,406		$	13,219		$	78,774
Charge-offs		(5,199	)		(7,548	)		(3,718	)		(1,549	)		(13,372	)		(31,386	)
Recoveries		3,381			1,243			2,340			991			4,336			12,291
Net provision for loan losses		11,152			2,072			(3,698	)		64			8,152			17,742
Ending balance	$	30,109		$	7,182		$	21,883		$	5,912		$	12,335		$	77,421
Ending balance:
Individually evaluated for impairment	$	325		$	211		$	946		$	—		$	—		$	1,482
Collectively evaluated for impairment		29,784			6,971			20,937			5,912			12,335			75,939
Loans:
Ending balance:	$	3,633,490		$	738,983		$	1,816,402		$	1,124,649		$	1,387,243		$	8,700,767
Individually evaluated for impairment		8,911			16,044			21,170			—			—			46,125
Collectively evaluated for impairment		3,624,579			722,939			1,795,232			1,124,649			1,387,243			8,654,642
Acquired loans
Allowance for loan losses:
Beginning balance	$	788		$	—		$	—		$	—		$	—		$	788
Charge-offs		—			—			—			—			—			—
Recoveries		—			—			—			—			—			—
Net provision for loan losses		(788	)		—			463			—			—			(325	)
Ending balance	$	—		$	—		$	463		$	—		$	—		$	463
Ending balance:
Individually evaluated for impairment	$	—		$	—		$	463		$	—		$	—		$	463
Amounts related to acquired-impaired loans		—			—			—			—			—			—
Collectively evaluated for impairment		—			—			—			—			—			—
Loans:
Ending balance:	$	967,485		$	158,228		$	1,038,287		$	347,054		$	130,649		$	2,641,703
Individually evaluated for impairment		2,179			730			2,371			502			—			5,782
Acquired-impaired loans		18,967			15,080			25,432			5,387			105			64,971
Collectively evaluated for impairment		946,339			142,418			1,010,484			341,165			130,544			2,570,950
	Commercial			Construction			Commercial			Residential			Consumer			Total
	non-real			and land			real estate			mortgages
	estate			development
(In thousands)	Nine Months Ended September 30, 2013
Covered loans
Allowance for loan losses:
Beginning balance	$	2,162		$	5,623		$	9,433		$	30,471		$	8,920		$	56,609
Charge-offs		(681	)		(1,784	)		(4,316	)		(947	)		(1,145	)		(8,873	)
Recoveries		90			554			2,395			13			67			3,119
Net provision for loan losses		(328	)		(1,600	)		1,197			4,723			3,995			7,987
Increase (Decrease) in FDIC loss share receivable		447			(314	)		(732	)		1,261			835			1,497
Ending balance	$	1,690		$	2,479		$	7,977		$	35,521		$	12,672		$	60,339
Ending balance:
Individually evaluated for impairment	$	—		$	—		$	—		$	—		$	—		$	—
Amounts related to acquired-impaired loans		1,690			2,479			7,977			35,521			12,672			60,339
Collectively evaluated for impairment		—			—			—			—			—			—
Loans:
Ending balance:	$	24,340		$	23,197		$	60,280		$	223,494		$	60,691		$	392,002
Individually evaluated for impairment		—			—			—			—			—			—
Acquired-impaired loans		24,340			23,197			60,280			223,494			60,691			392,002
Collectively evaluated for impairment		—			—			—			—			—			—
Total loans
Allowance for loan losses:
Beginning balance	$	23,725		$	17,038		$	36,392		$	36,877		$	22,139		$	136,171
Charge-offs		(5,880	)		(9,332	)		(8,034	)		(2,496	)		(14,517	)		(40,259	)
Recoveries		3,471			1,797			4,735			1,004			4,403			15,410
Net provision for loan losses		10,036			472			(2,038	)		4,787			12,147			25,404
Increase (Decrease) in FDIC loss share receivable		447			(314	)		(732	)		1,261			835			1,497
Ending balance	$	31,799		$	9,661		$	30,323		$	41,433		$	25,007		$	138,223
Ending balance:
Individually evaluated for impairment	$	325		$	211		$	1,409		$	—		$	—		$	1,945
Amounts related to acquired-impaired loans		1,690			2,479			7,977			35,521			12,672			60,339
Collectively evaluated for impairment		29,784			6,971			20,937			5,912			12,335			75,939
Loans:
Ending balance:	$	4,625,315		$	920,408		$	2,914,969		$	1,695,197		$	1,578,583		$	11,734,472
Individually evaluated for impairment		11,090			16,774			23,541			502			—			51,907
Acquired-impaired loans		43,307			38,277			85,712			228,881			60,796			456,973
Collectively evaluated for impairment		4,570,918			865,357			2,805,716			1,465,814			1,517,787			11,225,592
Summary of Composition of Non-Accrual Loans by Portfolio Segment	'
	The following tables show the composition of nonaccrual loans by portfolio segment and class. Acquired-impaired and certain covered loans are considered to be performing due to the application of the accretion method and are excluded from the table. Covered loans accounted for using the cost recovery method do not have an accretable yield and are included below as nonaccrual loans. Acquired-performing loans that have subsequently been placed on nonaccrual status are also included below.
		September 30,			December 31,
	Nonaccrual Loans	2014			2013
		(In thousands)
	Originated loans:
	Commercial non-real estate	$	9,279		$	10,119
	Construction and land development		6,083			13,171
	Commercial real estate		26,432			32,772
	Residential mortgages		21,326			13,449
	Consumer		5,242			4,802
	Total originated loans	$	68,362		$	74,313
	Acquired loans:
	Commercial non-real estate	$	1,857		$	3,209
	Construction and land development		3,275			1,990
	Commercial real estate		4,210			6,525
	Residential mortgages		1,353			8,262
	Consumer		877			1,814
	Total acquired loans	$	11,572		$	21,800
	Covered loans:
	Commercial non-real estate	$	—		$	2
	Construction and land development		1,539			1,539
	Commercial real estate		1,107			1,163
	Residential mortgages		394			544
	Consumer		180			296
	Total covered loans	$	3,220		$	3,544
	Total loans:
	Commercial non-real estate	$	11,136		$	13,330
	Construction and land development		10,897			16,700
	Commercial real estate		31,749			40,460
	Residential mortgages		23,073			22,255
	Consumer		6,299			6,912
	Total loans	$	83,154		$	99,657
Schedule of Troubled Debt Restructurings Occurred During Period by Portfolio Segment	'
	The tables below detail TDRs that were modified during the nine months ended September 30, 2014 and September 30, 2013 by portfolio segment and TDRs that subsequently defaulted within twelve months of modification (dollar amounts in thousands). All TDRs are rated substandard and individually evaluated for impairment.
		Nine Months Ended
		September 30, 2014									September 30, 2013
	Troubled Debt Restructurings:	Number of			Pre-Modification			Post-Modification			Number of			Pre-Modification			Post-Modification
		Contracts			Outstanding			Outstanding			Contracts			Outstanding			Outstanding
					Recorded			Recorded						Recorded			Recorded
					Investment			Investment						Investment			Investment
	Originated loans:
	Commercial non-real estate		—		$	—		$	—			1		$	925		$	920
	Construction and land development		—			—			—			—			—			—
	Commercial real estate		2			2,430			2,385			5			1,844			1,789
	Residential mortgages		4			1,495			848			2			971			854
	Consumer		—			—			—			—			—			—
	Total originated loans		6		$	3,925		$	3,233			8		$	3,740		$	3,563
	Acquired loans:
	Commercial non-real estate		—		$	—		$	—			—		$	—		$	—
	Construction and land development		—			—			—			—			—			—
	Commercial real estate		—			—			—			1			512			501
	Residential mortgages		—			—			—			1			515			493
	Consumer		—			—			—			—			—			—
	Total acquired loans		—		$	—		$	—			2		$	1,027		$	994
	Covered loans:
	Commercial non-real estate		—		$	—		$	—			—		$	—		$	—
	Construction and land development		—			—			—			—			—			—
	Commercial real estate		—			—			—			—			—			—
	Residential mortgages		—			—			—			—			—			—
	Consumer		—			—			—			—			—			—
	Total covered loans		—		$	—		$	—			—		$	—		$	—
	Total loans:
	Commercial non-real estate		—		$	—		$	—			1		$	925		$	920
	Construction and land development		—			—			—			—			—			—
	Commercial real estate		2			2,430			2,385			6			2,356			2,290
	Residential mortgages		4			1,495			848			3			1,486			1,347
	Consumer		—			—			—			—			—			—
	Total loans		6		$	3,925		$	3,233			10		$	4,767		$	4,557
Summary of Impaired Loans Disaggregated by Class	'
	The tables below present loans that are individually evaluated for impairment disaggregated by class at September 30, 2014 and December 31, 2013:
	September 30, 2014	Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Income
					Balance						Investment			Recognized
		(In thousands)
	Originated loans:
	With no related allowance recorded:
	Commercial non-real estate	$	1,498		$	2,111		$	—		$	1,157		$	31
	Construction and land development		3,320			5,459			—			3,218			112
	Commercial real estate		10,502			13,011			—			8,428			246
	Residential mortgages		263			647			—			88			1
	Consumer		—			—			—			—			—
			15,583			21,228			—			12,891			390
	With an allowance recorded:
	Commercial non-real estate	$	4,084		$	4,173		$	24		$	5,922			77
	Construction and land development		3,297			3,815			250			6,578			100
	Commercial real estate		3,984			4,304			98			7,417			75
	Residential mortgages		2,449			2,758			382			2,189			28
	Consumer		—			—			—			—			—
			13,814			15,050			754			22,106			280
	Total:
	Commercial non-real estate		5,582			6,284			24			7,079			108
	Construction and land development		6,617			9,274			250			9,796			212
	Commercial real estate		14,486			17,315			98			15,845			321
	Residential mortgages		2,712			3,405			382			2,277			29
	Consumer		—			—			—			—			—
	Total originated loans	$	29,397		$	36,278		$	754		$	34,997		$	670
	Acquired loans:
	With no related allowance recorded:
	Commercial non-real estate	$	—		$	1,730		$	—		$	357		$	—
	Construction and land development		—			—			—			121			—
	Commercial real estate		—			—			—			311			—
	Residential mortgages		28			68			—			88			—
	Consumer		—			—			—			—			—
			28			1,798			—			877			—
	With an allowance recorded:
	Commercial non-real estate		931			1,070			92		$	1,304			118
	Construction and land development		2,284			4,835			426			1,130			45
	Commercial real estate		458			493			46			1,305			61
	Residential mortgages		—			—			—			—			—
	Consumer		—			—			—			—			—
			3,673			6,398			564			3,739			224
	Total:
	Commercial non-real estate		931			2,800			92			1,661			118
	Construction and land development		2,284			4,835			426			1,251			45
	Commercial real estate		458			493			46			1,616			61
	Residential mortgages		28			68			—			88			—
	Consumer		—			—			—			—			—
	Total acquired loans	$	3,701		$	8,196		$	564		$	4,616		$	224
	September 30, 2014	Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Income
					Balance						Investment			Recognized
	Covered loans:
	With no related allowance recorded:
	Commercial non-real estate	$	—		$	—		$	—		$	—		$	—
	Construction and land development		—			—			—			—			—
	Commercial real estate		—			—			—			—			—
	Residential mortgages		—			—			—			—			—
	Consumer		—			—			—			—			—
			—			—			—			—			—
	With an allowance recorded:
	Commercial non-real estate		—			—			—			—			—
	Construction and land development		—			—			—			—			—
Commercial real estate		—			—			—			—			—
Residential mortgages		—			—			—			—			—
Consumer		—			—			—			—			—
		—			—			—			—			—
Total:
Commercial non-real estate		—			—			—			—			—
Construction and land development		—			—			—			—			—
Commercial real estate		—			—			—			—			—
Residential mortgages		—			—			—			—			—
Consumer		—			—			—			—			—
Total covered loans	$	—		$	—		$	—		$	—		$	—
Total loans:
With no related allowance recorded:
Commercial non-real estate	$	1,498		$	3,841		$	—		$	1,514		$	31
Construction and land development		3,320			5,459			—			3,339			112
Commercial real estate		10,502			13,011			—			8,739			246
Residential mortgages		291			715			—			176			1
Consumer		—			—			—			—			—
		15,611			23,026			—			13,768			390
With an allowance recorded:
Commercial non-real estate		5,015			5,243			116			7,226			195
Construction and land development		5,581			8,650			676			7,708			145
Commercial real estate		4,442			4,797			144			8,722			136
Residential mortgages		2,449			2,758			382			2,189			28
Consumer		—			—			—			—			—
		17,487			21,448			1,318			25,845			504
Total:
Commercial non-real estate		6,513			9,084			116			8,740			226
Construction and land development		8,901			14,109			676			11,047			257
Commercial real estate		14,944			17,808			144			17,461			382
Residential mortgages		2,740			3,473			382			2,365			29
Consumer		—			—			—			—			—
Total loans	$	33,098		$	44,474		$	1,318		$	39,613		$	894
December 31, 2013	Recorded			Unpaid			Related			Average			Interest
	Investment			Principal			Allowance			Recorded			Income
				Balance						Investment			Recognized
	(In thousands)
Originated loans:
With no related allowance recorded:
Commercial non-real estate	$	329		$	442		$	—		$	235		$	18
Construction and land development		4,101			5,131			—			2,780			82
Commercial real estate		5,321			7,458			—			15,886			374
Residential mortgages		—			—			—			262			—
Consumer		—			—			—			1,013			—
		9,751			13,031			—			20,176			474
With an allowance recorded:
Commercial non-real estate		4,965			5,303			477			8,936			180
Construction and land development		6,498			8,343			22			2,549			—
Commercial real estate		8,708			9,090			268			19,683			460
Residential mortgages		605			620			1			228			—
Consumer		—			—			—			1,025			—
		20,776			23,356			768			32,421			640
Total:
Commercial non-real estate		5,294			5,745			477			9,171			198
Construction and land development		10,599			13,474			22			5,329			82
Commercial real estate		14,029			16,548			268			35,569			834
Residential mortgages		605			620			1			490			—
Consumer		—			—			—			2,038			—
Total originated loans	$	30,527		$	36,387		$	768		$	52,597		$	1,114
Acquired loans:
With no related allowance recorded:
Commercial non-real estate	$	2,141		$	3,275		$	—		$	865		$	8
Construction and land development		728			1,142			—			296			3
Commercial real estate		1,865			2,634			—			1,339			49
Residential mortgages		473			507			—			407			—
Consumer		—			—			—			—			—
		5,207			7,558			—			2,907			60
With an allowance recorded:
Commercial non-real estate		—			—			—			2,747			63
Construction and land development		—			—			—			157			—
Commercial real estate		—			—			—			2,663			—
Residential mortgages		—			—			—			845			—
Consumer		—			—			—			—			—
		—			—			—			6,412			63
Total:
Commercial non-real estate		2,141			3,275			—			3,612			71
Construction and land development		728			1,142			—			453			3
Commercial real estate		1,865			2,634			—			4,002			49
Residential mortgages		473			507			—			1,252			—
Consumer		—			—			—			—			—
Total acquired loans	$	5,207		$	7,558		$	—		$	9,319		$	123
				Unpaid						Average			Interest
	Recorded			Principal			Related			Recorded			Income
December 31, 2013	Investment			Balance			Allowance			Investment			Recognized
Covered loans:
With no related allowance recorded:
Commercial non-real estate	$	—		$	—		$	—		$	—		$	—
Construction and land development		—			—			—			—			—
Commercial real estate		—			—			—			—			—
Residential mortgages		—			—			—			—			—
Consumer		—			—			—			—			—
		—			—			—			—			—
With an allowance recorded:
Commercial non-real estate		—			—			—			—			—
Construction and land development		—			—			—			—			—
Commercial real estate		—			—			—			—			—
Residential mortgages		—			—			—			—			—
Consumer		—			—			—			—			—
		—			—			—			—			—
Total:
Commercial non-real estate		—			—			—			—			—
Construction and land development		—			—			—			—			—
Commercial real estate		—			—			—			—			—
Residential mortgages		—			—			—			—			—
Consumer		—			—			—			—			—
Total covered loans	$	—		$	—		$	—		$	—		$	—
Total loans:
With no related allowance recorded:
Commercial non-real estate	$	2,470		$	3,717		$	—		$	1,100		$	26
Construction and land development		4,829			6,273			—			3,076			85
Commercial real estate		7,186			10,092			—			17,225			423
Residential mortgages		473			507			—			669			—
Consumer		—			—			—			1,013			—
		14,958			20,589			—			23,083			534
With an allowance recorded:
Commercial non-real estate		4,965			5,303			477			11,683			243
Construction and land development		6,498			8,343			22			2,706			—
Commercial real estate		8,708			9,090			268			22,346			460
Residential mortgages		605			620			1			1,073			—
Consumer		—			—			—			1,025			—
		20,776			23,356			768			38,833			703
Total:
Commercial non-real estate		7,435			9,020			477			12,783			269
Construction and land development		11,327			14,616			22			5,782			85
Commercial real estate		15,894			19,182			268			39,571			883
Residential mortgages		1,078			1,127			1			1,742			—
Consumer		—			—			—			2,038			—
Total loans	$	35,734		$	43,945		$	768		$	61,916		$	1,237
Summary of Age Analysis of Past Due Loans	'
	The following tables present the age analysis of past due loans at September 30, 2014 and December 31, 2013:
																				Recorded
								Greater than												investment
		30-59 days			60-89 days			90 days			Total						Total			> 90 days
	September 30, 2014	past due			past due			past due			past due			Current			Loans			and still accruing
											(In thousands)
	Originated loans:
	Commercial non-real estate	$	4,137		$	4,039		$	3,111		$	11,287		$	4,795,453		$	4,806,740		$	259
	Construction and land development		1,159			651			6,185			7,995			966,447			974,442			1,443
	Commercial real estate		3,524			2,170			12,271			17,965			2,227,890			2,245,855			257
	Residential mortgages		606			5,071			10,503			16,180			1,619,282			1,635,462			220
	Consumer		4,539			2,556			4,290			11,385			1,611,684			1,623,069			2,970
	Total	$	13,965		$	14,487		$	36,360		$	64,812		$	11,220,756		$	11,285,568		$	5,149
	Acquired loans:
	Commercial non-real estate	$	151		$	95		$	1,734		$	1,980		$	767,246		$	769,226		$	—
	Construction and land development		231			1,649			1,400			3,280			107,014			110,294			17
	Commercial real estate		522			641			3,534			4,697			808,732			813,429			1,471
	Residential mortgages		27			—			228			255			37,484			37,739			—
	Consumer		358			241			593			1,192			50,296			51,488			30
	Total	$	1,289		$	2,626		$	7,489		$	11,404		$	1,770,772		$	1,782,176		$	1,518
	Covered loans:
	Commercial non-real estate	$	—		$	—		$	—		$	—		$	11,171		$	11,171		$	—
	Construction and land development		—			—			—			—			11,166			11,166			—
	Commercial real estate		—			—			—			—			41,550			41,550			—
	Residential mortgages		—			149			—			149			185,140			185,289			—
	Consumer		1			—			35			36			31,618			31,654			—
	Total	$	1		$	149		$	35		$	185		$	280,645		$	280,830		$	—
	Total loans:
	Commercial non-real estate	$	4,288		$	4,134		$	4,845		$	13,267		$	5,573,870		$	5,587,137		$	259
	Construction and land development		1,390			2,300			7,585			11,275			1,084,627			1,095,902			1,460
	Commercial real estate		4,046			2,811			15,805			22,662			3,078,172			3,100,834			1,728
	Residential mortgages		633			5,220			10,731			16,584			1,841,906			1,858,490			220
	Consumer		4,898			2,797			4,918			12,613			1,693,598			1,706,211			3,000
	Total	$	15,255		$	17,262		$	43,884		$	76,401		$	13,272,173		$	13,348,574		$	6,667
																				Recorded
								Greater than												investment
		30-59 days			60-89 days			90 days			Total						Total			> 90 days
	December 31, 2013	past due			past due			past due			past due			Current			Loans			and still accruing
											(In thousands)
	Originated loans:
	Commercial non-real estate	$	11,645		$	1,203		$	4,803		$	17,651		$	4,096,186		$	4,113,837		$	521
	Construction and land development		5,877			1,264			5,970			13,111			739,270			752,381			—
	Commercial real estate		8,178			5,744			14,620			28,542			1,993,986			2,022,528			420
	Residential mortgages		12,410			3,870			3,540			19,820			1,176,436			1,196,256			—
	Consumer		8,798			1,913			3,823			14,534			1,394,596			1,409,130			2,344
	Total	$	46,908		$	13,994		$	32,756		$	93,658		$	9,400,474		$	9,494,132		$	3,285
	Acquired loans:
	Commercial non-real estate	$	1,982		$	2,332		$	1,467		$	5,781		$	921,216		$	926,997		$	541
	Construction and land development		862			1,529			1,161			3,552			139,379			142,931			541
	Commercial real estate		3,742			1,345			9,026			14,113			953,035			967,148			5,853
	Residential mortgages		5,632			2,698			5,503			13,833			301,507			315,340			72
	Consumer		1,029			120			1,013			2,162			117,441			119,603			82
	Total	$	13,247		$	8,024		$	18,170		$	39,441		$	2,432,578		$	2,472,019		$	7,089
	Covered loans:
	Commercial non-real estate	$	—		$	—		$	—		$	—		$	23,390		$	23,390		$	—
	Construction and land development		—			—			1,539			1,539			18,690			20,229			—
	Commercial real estate		—			—			675			675			52,490			53,165			—
	Residential mortgages		—			—			3			3			209,015			209,018			—
	Consumer		—			—			—			—			52,864			52,864			—
	Total	$	—		$	—		$	2,217		$	2,217		$	356,449		$	358,666		$	—
	Total loans:
	Commercial non-real estate	$	13,627		$	3,535		$	6,270		$	23,432		$	5,040,792		$	5,064,224		$	1,062
	Construction and land development		6,739			2,793			8,670			18,202			897,339			915,541			541
Commercial real estate		11,920			7,089			24,321			43,330			2,999,511			3,042,841			6,273
Residential mortgages		18,042			6,568			9,046			33,656			1,686,958			1,720,614			72
Consumer		9,827			2,033			4,836			16,696			1,564,901			1,581,597			2,426
Total	$	60,155		$	22,018		$	53,143		$	135,316		$	12,189,501		$	12,324,817		$	10,374
Changes in Carrying Amount of Covered Acquired Loans and Accretable Yield for Loans Receivable	'
	Changes in the carrying amount of acquired-impaired loans and accretable yield are presented in the following table for the nine months ended September 30, 2014 and the year ended December 31, 2013:
		September 30, 2014												December 31, 2013
		Covered						Noncovered						Covered						Noncovered
		Carrying						Carrying						Carrying						Carrying
		Amount			Accretable			Amount			Accretable			Amount			Accretable			Amount			Accretable
		of Loans			Yield			of Loans			Yield			of Loans			Yield			of Loans			Yield
	(In thousands)
	Balance at beginning of period	$	358,666		$	122,715		$	68,075		$	131,370		$	515,823		$	115,594		$	141,201		$	203,186
	Additions		—			—			—			—			—			—			—			—
	Payments received, net		(92,890	)		(953	)		(47,979	)		(28,487	)		(189,987	)		(1,298	)		(116,187	)		(47,330	)
	Accretion		15,054			(15,054	)		35,741			(35,741	)		32,830			(32,830	)		43,061			(43,061	)
	Increase (Decrease) in expected cash flows based on actual cash flows and changes in cash flow assumptions		—			1,783			—			(380	)		—			(17,433	)		—			3,894
	Net transfers from nonaccretable difference to accretable yield		—			11,917			—			19,076			—			58,682			—			14,681
	Balance at end of period	$	280,830		$	120,408		$	55,837		$	85,838		$	358,666		$	122,715		$	68,075		$	131,370
Commercial Non-Real Estate [Member]	'
Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based on Payment Activity	'
	The following tables present the credit quality indicators of the Company’s various classes of loans at September 30, 2014 and December 31, 2013.
	Commercial Non-Real Estate Credit Exposure
	Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
	Grade:
	Pass	$	4,656,899		$	698,111		$	1,856		$	5,356,866		$	3,990,320		$	846,134		$	10,477		$	4,846,931
	Pass-Watch		58,894			32,372			—			91,266			46,734			44,105			9			90,848
	Special Mention		26,869			26,635			521			54,025			41,812			19,915			2,897			64,624
	Substandard		63,959			12,108			8,794			84,861			34,276			16,125			9,662			60,063
	Doubtful		119			—			—			119			695			718			345			1,758
	Loss		—			—			—			—			—			—			—			—
	Total	$	4,806,740		$	769,226		$	11,171		$	5,587,137		$	4,113,837		$	926,997		$	23,390		$	5,064,224
Construction and Land Development [Member]	'
Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based on Payment Activity	'
	Construction Credit Exposure
	Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
	Grade:
	Pass	$	923,800		$	82,067		$	2,323		$	1,008,190		$	709,261		$	112,773		$	1		$	822,035
	Pass-Watch		17,576			2,911			1,000			21,487			7,817			1,907			1,226			10,950
	Special Mention		5,832			5,737			29			11,598			3,926			9,409			276			13,611
	Substandard		27,234			19,579			7,814			54,627			31,377			18,842			11,498			61,717
	Doubtful		—			—			—			—			—			—			7,228			7,228
	Loss		—			—			—			—			—			—			—			—
	Total	$	974,442		$	110,294		$	11,166		$	1,095,902		$	752,381		$	142,931		$	20,229		$	915,541
Commercial Real Estate [Member]	'
Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based by Internally Assigned Grade	'
	Commercial Real Estate Credit Exposure
	Credit Risk Profile by Internally Assigned Grade
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
	Grade:
	Pass	$	2,048,886		$	758,092		$	6,805		$	2,813,783		$	1,864,115		$	896,578		$	1,678		$	2,762,371
	Pass-Watch		83,729			8,725			5,811			98,265			49,578			9,530			10,266			69,374
	Special Mention		25,842			9,029			863			35,734			15,785			19,798			1,999			37,582
	Substandard		87,369			37,583			28,039			152,991			93,034			41,242			31,350			165,626
	Doubtful		29			—			32			61			16			—			7,872			7,888
	Loss		—			—			—			—			—			—			—			—
	Total	$	2,245,855		$	813,429		$	41,550		$	3,100,834		$	2,022,528		$	967,148		$	53,165		$	3,042,841
Residential Mortgages [Member]	'
Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based by Internally Assigned Grade	'
	Residential Mortgage Credit Exposure
	Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
		(In thousands)												(In thousands)
	Performing	$	1,624,959		$	37,511		$	185,289		$	1,847,759		$	1,182,266		$	307,078		$	209,015		$	1,698,359
	Nonperforming		10,503			228			—			10,731			13,990			8,262			3			22,255
	Total	$	1,635,462		$	37,739		$	185,289		$	1,858,490		$	1,196,256		$	315,340		$	209,018		$	1,720,614
Consumer [Member]	'
Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based on Payment Activity	'
	Consumer Credit Exposure
	Credit Risk Profile Based on Payment Activity
		September 30, 2014												December 31, 2013
		Originated			Acquired			Covered			Total			Originated			Acquired			Covered			Total
					(In thousands)												(In thousands)
	Performing	$	1,618,779		$	50,895		$	31,619		$	1,701,293		$	1,404,032		$	117,789		$	52,864		$	1,574,685
	Nonperforming		4,290			593			35			4,918			5,098			1,814			—			6,912
	Total	$	1,623,069		$	51,488		$	31,654		$	1,706,211		$	1,409,130		$	119,603		$	52,864		$	1,581,597
Troubled Debt Restructurings That Subsequently Defaulted [Member]	'
Schedule of Troubled Debt Restructurings Occurred During Period by Portfolio Segment	'
		Nine Months Ended
		30-Sep-14						30-Sep-13
	Troubled Debt Restructurings That	Number of			Recorded			Number of			Recorded
	Subsequently Defaulted:	Contracts			Investment			Contracts			Investment
	Originated loans:
	Commercial non-real estate		1		$	909			—		$	—
	Construction and land development		—			—			—			—
	Commercial real estate		—			—			—			—
	Residential mortgages		—			—			—			—
	Consumer		—			—			—			—
	Total originated loans		1		$	909			—		$	—
	Acquired loans:
	Commercial non-real estate		—		$	—			—		$	—
	Construction and land development		—			—			—			—
	Commercial real estate		—			—			—			—
	Residential mortgages		—			—			—			—
	Consumer		—			—			—			—
	Total acquired loans		—		$	—			—		$	—
	Covered loans:
	Commercial non-real estate		—		$	—			—		$	—
	Construction and land development		—			—			—			—
	Commercial real estate		—			—			—			—
	Residential mortgages		—			—			—			—
	Consumer		—			—			—			—
	Total covered loans		—		$	—			—		$	—
	Total loans:
	Commercial non-real estate		1		$	909			—		$	—
	Construction and land development		—			—			—			—
	Commercial real estate		—			—			—			—
	Residential mortgages		—			—			—			—
	Consumer		—			—			—			—
	Total loans		1		$	909			—		$	—

Fair_Value_Tables

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	'
	The following tables present for each of the fair value hierarchy levels the Company’s assets and liabilities that are measured at fair value (in thousands) on a recurring basis in the consolidated balance sheets.
			September 30, 2014
			Level 1		Level 2		Total
	Assets
	Available for sale debt securities:
	U.S. Treasury and government agency securities		$	300,702	$	—	$	300,702
	Municipal obligations			—		18,767		18,767
	Corporate debt securities			3,500		—		3,500
	Mortgage-backed securities			—		1,241,223		1,241,223
	Collateralized mortgage obligations			—		88,558		88,558
	Equity securities			9,660		—		9,660
	Total available for sale securities			313,862		1,348,548		1,662,410
	Derivative assets (1)			—		16,012		16,012
	Total recurring fair value measurements - assets		$	313,862	$	1,364,560	$	1,678,422
	Liabilities
	Derivative liabilities (1)		$	—	$	16,440	$	16,440
	Total recurring fair value measurements - liabilities		$	—	$	16,440	$	16,440
	-1	For further disaggregation of derivative assets and liabilities, see Note 5 - Derivatives.
			December 31, 2013
			Level 1		Level 2		Total
	Assets
	Available for sale debt securities:
	U.S. Treasury and government agency securities		$	505	$	—	$	505
	Municipal obligations			—		35,961		35,961
	Corporate debt securities			3,500		—		3,500
	Mortgage-backed securities			—		1,276,958		1,276,958
	Collateralized mortgage obligations			—		94,125		94,125
	Equity securities			10,723		—		10,723
	Total available for sale securities			14,728		1,407,044		1,421,772
	Derivative assets (1)			—		15,579		15,579
	Total recurring fair value measurements - assets		$	14,728	$	1,422,623	$	1,437,351
	Liabilities
	Derivative liabilities (1)		$	—	$	15,006	$	15,006
	Total recurring fair value measurements - liabilities		$	—	$	15,006	$	15,006
	-1	For further disaggregation of derivative assets and liabilities, see Note 5 - Derivatives.
Schedule of Financial Assets Measured at Fair Value on Nonrecurring Basis	'
	The following tables present the Company’s financial assets that are measured at fair value (in thousands) on a nonrecurring basis for each of the fair value hierarchy levels.
			September 30, 2014
			Level 1		Level 2		Level 3		Total
	Collateral-dependent impaired loans		$	—	$	34,482	$	—	$	34,482
	Other real estate owned			—		—		20,742		20,742
	Total nonrecurring fair value measurements		$	—	$	34,482	$	20,742	$	55,224
			December 31, 2013
			Level 1		Level 2		Level 3		Total
	Collateral-dependent impaired loans		$	—	$	24,392	$	—	$	24,392
	Other real estate owned			—		—		25,525		25,525
	Total nonrecurring fair value measurements		$	—	$	24,392	$	25,525	$	49,917
Schedule of Estimated Fair Values of Financial Instruments	'
	The following tables present the estimated fair values of the Company’s financial instruments by fair value hierarchy levels and the corresponding carrying amount at September 30, 2014 and December 31, 2013 (in thousands):
			September 30, 2014
									Total		Carrying
			Level 1		Level 2		Level 3		Fair Value		Amount
	Financial assets:
	Cash, interest-bearing bank deposits, and federal funds sold		$	803,917	$	—	$	—	$	803,917	$	803,917
	Available for sale securities			313,862		1,348,548		—		1,662,410		1,662,410
	Held to maturity securities			—		2,253,219		—		2,253,219		2,250,960
	Loans, net			—		34,482		13,081,700		13,116,182		13,223,002
	Loans held for sale			—		15,098		—		15,098		15,098
	Accrued interest receivable			44,164		—		—		44,164		44,164
	Derivative financial instruments			—		16,012		—		16,012		16,012
	Financial liabilities:
	Deposits		$	—	$	—	$	15,434,876	$	15,434,876	$	15,736,694
	Federal funds purchased			7,625		—		—		7,625		7,625
	Securities sold under agreements to repurchase			599,184		—		—		599,184		599,184
	FHLB borrowings			565,000		—		—		565,000		565,000
	Long-term debt			—		344,636		—		344,636		376,452
	Accrued interest payable			5,663		—		—		5,663		5,663
	Derivative financial instruments			—		16,440		—		16,440		16,440
			December 31, 2013
									Total		Carrying
			Level 1		Level 2		Level 3		Fair Value		Amount
	Financial assets:
	Cash, interest-bearing bank deposits, and federal funds sold		$	617,280	$	—	$	—	$	617,280	$	617,280
	Available for sale securities			14,728		1,407,044		—		1,421,772		1,421,772
	Held to maturity securities			100,316		2,476,268		—		2,576,584		2,611,352
	Loans, net			—		24,392		12,023,330		12,047,722		12,191,191
	Loans held for sale			—		24,515		—		24,515		24,515
	Accrued interest receivable			42,977		—		—		42,977		42,977
	Derivative financial instruments			—		15,579		—		15,579		15,579
	Financial liabilities:
	Deposits		$	—	$	—	$	15,352,024	$	15,352,024	$	15,360,516
	Federal funds purchased			7,725		—		—		7,725		7,725
	Securities sold under agreements to repurchase			650,235		—		—		650,235		650,235
	Long-term debt			—		385,557		—		385,557		385,826
	Accrued interest payable			4,353		—		—		4,353		4,353
	Derivative financial instruments			—		15,006		—		15,006		15,006

Derivatives_Tables

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Fair Values of Derivative Instruments on Balance Sheet	'
	The table below presents the notional amounts and fair values (in thousands) of the Company’s derivative financial instruments as well as their classification on the consolidated balance sheets as of September 30, 2014 and December 31, 2013.
													Fair Values (1)
					Notional Amounts								Assets								Liabilities
			Type of		September				December				September				December				September				December
			Hedge		30, 2014				31, 2013				30, 2014				31, 2013				30, 2014				31, 2013
	Derivatives not designated as hedging instruments:
	Interest rate swaps (2)		N/A		$	753,382			$	650,667			$	14,585			$	14,147			$	14,974			$	13,777
	Risk participation agreements		N/A			80,989				19,736				105				2				156				2
	Forward commitments to sell residential mortgage loans		N/A			40,873				45,910				56				326				640				115
	Interest rate-lock commitments on residential mortgage loans		N/A			28,025				25,956				595				56				27				107
	Foreign exchange forward contracts		N/A			37,127				21,299				671				1,048				643				1,005
					$	940,396			$	763,568			$	16,012			$	15,579			$	16,440			$	15,006
	-1	Derivative assets and liabilities are reported with other assets or other liabilities, respectively, in the consolidated balance sheets.
	-2	The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.
Offsetting Derivative Assets and Liabilities	'
	Offsetting information in regards to derivative assets and liabilities subject to master netting agreements at September 30, 2014 and December 31, 2013 is presented in the following tables (in thousands):
							Gross				Net Amounts				Gross
							Amounts				Presented in				Amounts
							Offset in								Not Offset
															in the
															Statement
															of Financial
	Description		Gross				the				the				Financial				Cash				Net
			Amounts				Statement of				Statement				Instruments				Collateral				Amount
			Recognized				Financial				of Financial
							Position				Position
	As of September 30, 2014
	Derivative Assets		$	14,690			$	—			$	14,690			$	2,206			$	—			$	12,484
	Total		$	14,690			$	—			$	14,690			$	2,206			$	—			$	12,484
	Derivative Liabilities		$	15,129			$	—			$	15,129			$	2,206			$	16,767			$	(3,844	)
	Total		$	15,129			$	—			$	15,129			$	2,206			$	16,767			$	(3,844	)
	As of December 31, 2013
	Derivative Assets		$	14,149			$	—			$	14,149			$	3,462			$	—			$	10,687
	Total		$	14,149			$	—			$	14,149			$	3,462			$	—			$	10,687
	Derivative Liabilities		$	13,779			$	—			$	13,779			$	3,462			$	7,406			$	2,911
	Total		$	13,779			$	—			$	13,779			$	3,462			$	7,406			$	2,911

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Components of Accumulated Other Comprehensive Income (Loss)	'
	The components of AOCI and changes in those components are presented in the following table (in thousands).
			Available			HTM Securities						Loss on
			for Sale			Transferred			Employee			Effective Cash
			Securities			from AFS			Benefit Plans			Flow Hedges			Total
	Balance, January 1, 2013		$	38,854		$	19,090		$	(80,688	)	$	(181	)	$	(22,925	)
	Other comprehensive income before income taxes:
	Net change in unrealized (loss) gain			(96,070	)		—			—			(4	)		(96,074	)
	Transfer of net unrealized gain from AFS to HTM, net of cumulative tax effect			36,208			(36,208	)		—			—			—
	Reclassification of net losses realized and included in earnings			—			—			5,534			301			5,835
	Amortization of unrealized net gain on securities transferred to HTM			—			(7,099	)		—			—			(7,099	)
	Income tax (benefit) expense			(35,115	)		(2,563	)		2,070			116			(35,492	)
	Balance, September 30, 2013		$	14,107		$	(21,654	)	$	(77,224	)	$	—		$	(84,771	)
	Balance, January 1, 2014		$	8,263		$	(21,189	)	$	(22,453	)	$	—		$	(35,379	)
	Other comprehensive income before income taxes:
	Net change in unrealized gain			9,119			—			—			—			9,119
	Reclassification of net losses realized and included in earnings			—			—			2,195			—			2,195
	Amortization of unrealized net gain on securities transferred to HTM			—			2,463			—			—			2,463
	Income tax expense			3,309			879			903			—			5,091
	Balance, September 30, 2014		$	14,073		$	(19,605	)	$	(21,161	)	$	—		$	(26,693	)
Summary of Line Item Affected by Amounts Reclassified from Accumulated Other Comprehensive Income	'
	The following table shows the line item affected by amounts reclassified from accumulated other comprehensive income:
	Amount reclassified from AOCI		Nine Months Ended						Increase (decrease)
			September 30,						in affected line item
	(in thousands)		2014			2013			on the income statement
	Amortization/accretion of unrealized net gain/(loss) on securities transferred to HTM		$	2,463		$	(7,099	)	Interest income
	Tax effect			879			(2,563	)	Income taxes
	Net of tax			1,584			(4,536	)	Net income
	Amortization of defined benefit pension and post-retirement items		$	293		$	5,534		(a) Employee benefits expense
	Tax effect			103			2,070		Income taxes
	Net of tax			190			3,464		Net income
	Gains and losses on cash flow hedges		$	—		$	301		Interest expense
	Tax effect			—			105		Income taxes
	Net of tax			—			196		Net income
	Total reclassifications, net of tax		$	1,774		$	(876	)	Net income
	(a)	These accumulated other comprehensive income components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 9 for add

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Computation of Earnings Per Common Share	'
	A summary of the information used in the computation of earnings per common share follows (in thousands, except per share amounts):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2014		2013		2014		2013
	Numerator:
	Net income to common shareholders	$	46,553	$	33,202	$	135,630	$	128,640
	Net income allocated to participating securities - basic and diluted		883		616		2,783		2,398
	Net income allocated to common shareholders - basic and diluted	$	45,670	$	32,586	$	132,847	$	126,242
	Denominator:
	Weighted average common shares - basic		81,721		82,091		81,965		83,404
	Dilutive potential common shares		221		114		239		92
	Weighted average common shares - diluted		81,942		82,205		82,204		83,496
	Earnings per common share:
	Basic	$	0.56	$	0.4	$	1.62	$	1.51
	Diluted	$	0.56	$	0.4	$	1.62	$	1.51

ShareBased_Payment_Arrangement1

Share-Based Payment Arrangements (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Option Activity Under Stock Option Plans	'
	A summary of option activity for the nine months ended September 30, 2014 is presented below:
							Weighted
							Average
					Weighted		Remaining
					Average		Contractual		Aggregate
		Number of			Exercise		Term		Intrinsic
	Options	Shares			Price		(Years)		Value ($000)
	Outstanding at January 1, 2014		1,332,656		$	38.85
	Exercised		(32,618	)		29.51
	Cancelled/Forfeited		(16,549	)		38.26
	Expired		(113,447	)		63.41
	Outstanding at September 30, 2014		1,170,042		$	36.74		4.4	$	799
	Exercisable at September 30, 2014		885,673		$	38.55		3.6	$	373
Schedule of Nonvested Restricted and Performance Shares	'
	A summary of the status of the Company’s nonvested restricted and performance shares as of September 30, 2014 and changes during the nine months ended September 30, 2014, is presented below. These restricted and performance shares are subject to service requirements.
					Weighted
					Average
		Number of			Grant Date
		Shares			Fair Value
	Nonvested at January 1, 2014		1,981,820		$	31.75
	Granted		120,396			36.23
	Vested		(272,788	)		32
	Forfeited		(85,873	)		31.69
	Nonvested at September 30, 2014		1,743,555		$	32.02

Retirement_Plans_Tables

Retirement Plans (Tables)	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Components of Net Periodic Benefits Cost	'
	The following table shows the components of net periodic benefits cost included in expense for the plans for the periods indicated (in thousands).
		Three Months Ended September 30,
		2014			2013			2014		2013
								Other Post-
		Pension benefits						retirement Benefits
	Service cost	$	3,230		$	3,969		$	31	$	52
	Interest cost		4,812			4,151			285		327
	Expected return on plan assets		(8,056	)		(6,982	)		—		—
	Amortization of net loss		7			1,605			91		459
	Net periodic benefit cost	$	(7	)	$	2,743		$	407	$	838
		Nine Months Ended September 30,
		2014			2013			2014		2013
								Other Post-
		Pension benefits						retirement Benefits
	Service cost	$	9,690		$	11,905		$	94	$	162
	Interest cost		14,438			12,457			855		987
	Expected return on plan assets		(24,167	)		(20,946	)		—		—
	Amortization of net loss		20			4,813			273		1,320
	Net periodic benefit cost	$	(19	)	$	8,229		$	1,222	$	2,469

Other_Noninterest_Income_Table

Other Noninterest Income (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Components of Other Noninterest Income	'
	Components of other noninterest income are as follows:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014			2013		2014		2013
	(In thousands)
	Income from bank owned life insurance	$	2,377		$	2,656	$	7,048	$	8,764
	Credit related fees		2,822			2,995		8,388		5,969
	Income from derivatives		191			1,257		1,431		3,296
	Net (loss) gain on sale of assets		(56	)		801		1,409		1,277
	Safety deposit box income		448			467		1,404		1,480
	Other miscellaneous		1,950			1,940		7,091		6,453
	Total other noninterest income	$	7,732		$	10,116	$	26,771	$	27,239

Other_Noninterest_Expense_Tabl

Other Noninterest Expense (Tables)	9 Months Ended
	Sep. 30, 2014
Text Block [Abstract]	'
Components of Other Noninterest Expense	'
	Components of other noninterest expense are as follows:
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
	(In thousands)	2014		2013		2014		2013
	Advertising	$	2,457	$	2,858	$	6,395	$	7,216
	Ad valorem and franchise taxes		3,098		2,809		8,397		7,193
	Printing and supplies		1,189		1,143		3,467		3,963
	Insurance expense		944		887		3,002		3,018
	Travel expense		1,009		1,074		2,966		3,475
	Entertainment and contributions		1,396		969		4,337		3,960
	Tax credit investment amortization		2,220		4,880		6,590		7,553
	Other miscellaneous		6,821		19,851		25,105		32,504
	Total other noninterest expense	$	19,134	$	34,471	$	60,259	$	68,882

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Tax Credit carry forward period	'20 years
Federal NMTC Investment [Member]	'
Period of tax credit earning	'7 years
Low Income Housing Investments [Member]	'
Period of tax credit earning	'10 years
Minimum [Member] | State NMTC Investment [Member]	'
Period of tax credit earning	'3 years
Maximum [Member] | State NMTC Investment [Member]	'
Period of tax credit earning	'5 years

Securities_Amortized_Cost_and_

Securities - Amortized Cost and Fair Value of Available for Sale Securities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	$1,640,299	$1,408,780
Securities available for sale, Gross Unrealized Gains	29,161	25,366
Securities available for sale, Gross Unrealized Losses	7,050	12,374
Securities Available for Sale, Fair Value	1,662,410	1,421,772
U.S. Treasury and government agency securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	300,257	504
Securities available for sale, Gross Unrealized Gains	446	2
Securities available for sale, Gross Unrealized Losses	1	1
Securities Available for Sale, Fair Value	300,702	505
Municipal obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	18,495	35,809
Securities available for sale, Gross Unrealized Gains	272	177
Securities available for sale, Gross Unrealized Losses	'	25
Securities Available for Sale, Fair Value	18,767	35,961
Corporate debt securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	3,500	3,500
Securities available for sale, Gross Unrealized Gains	'	'
Securities available for sale, Gross Unrealized Losses	'	'
Securities Available for Sale, Fair Value	3,500	3,500
Equity securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	8,784	9,965
Securities available for sale, Gross Unrealized Gains	877	785
Securities available for sale, Gross Unrealized Losses	1	27
Securities Available for Sale, Fair Value	9,660	10,723
Mortgage-backed securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	1,218,982	1,262,633
Securities available for sale, Gross Unrealized Gains	27,566	24,402
Securities available for sale, Gross Unrealized Losses	5,325	10,077
Securities Available for Sale, Fair Value	1,241,223	1,276,958
Collateralized mortgage obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Securities available for sale, amortized cost	90,281	96,369
Securities available for sale, Gross Unrealized Gains	'	'
Securities available for sale, Gross Unrealized Losses	1,723	2,244
Securities Available for Sale, Fair Value	$88,558	$94,125

Securities_Amortized_Cost_and_1

Securities - Amortized Cost and Fair Value of Held to Maturity Securities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]	'	'
Securities Held to Maturity, Amortized Cost	$2,250,960	$2,611,352
Securities Held to Maturity, Gross Unrealized Gains	21,225	2,593
Securities Held to Maturity, Gross Unrealized Losses	18,966	37,361
Securities Held to Maturity, Fair Value	2,253,219	2,576,584
U.S. Treasury and government agency securities [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Securities Held to Maturity, Amortized Cost	'	100,000
Securities Held to Maturity, Gross Unrealized Gains	'	316
Securities Held to Maturity, Gross Unrealized Losses	'	'
Securities Held to Maturity, Fair Value	'	100,316
Municipal obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Securities Held to Maturity, Amortized Cost	183,379	193,189
Securities Held to Maturity, Gross Unrealized Gains	2,911	919
Securities Held to Maturity, Gross Unrealized Losses	1,709	6,436
Securities Held to Maturity, Fair Value	184,581	187,672
Mortgage-backed securities [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Securities Held to Maturity, Amortized Cost	926,163	1,003,327
Securities Held to Maturity, Gross Unrealized Gains	12,426	296
Securities Held to Maturity, Gross Unrealized Losses	1,258	4,671
Securities Held to Maturity, Fair Value	937,331	998,952
Collateralized mortgage obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Securities Held to Maturity, Amortized Cost	1,141,418	1,314,836
Securities Held to Maturity, Gross Unrealized Gains	5,888	1,062
Securities Held to Maturity, Gross Unrealized Losses	15,999	26,254
Securities Held to Maturity, Fair Value	$1,131,307	$1,289,644

Securities_Amortized_Cost_and_2

Securities - Amortized Cost and Fair Value of Available for Sale Securities by Final Contractual Maturity (Detail) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity [Abstract]	'
Securities Available for Sale, Due in one year or less, Amortized Cost	$307,762
Securities Available for Sale, Due after one year through five years, Amortized Cost	153,025
Securities Available for Sale, Due after five years through ten years, Amortized Cost	218,513
Securities Available for Sale, Due after ten years, Amortized Cost	952,215
Total available for sale securities, Amortized Cost	1,631,515
Securities Available for Sale, Due in one year or less, Fair Value	308,233
Securities Available for Sale, Due after one year through five years, Fair Value	152,887
Securities Available for Sale, Due after five years through ten years, Fair Value	225,794
Securities Available for Sale, Due after ten years, Fair Value	965,836
Total available for sale securities, Fair Value	$1,652,750

Securities_Amortized_Cost_and_3

Securities - Amortized Cost and Fair Value of Held to Maturity Securities by Final Contractual Maturity (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amortized Cost And Estimated Fair Value Of Debt Securities By Contractual Maturity [Abstract]	'	'
Securities Held to Maturity, Due in one year or less, Amortized Cost	$5,302	'
Securities Held to Maturity, Due after one year through five years, Amortized Cost	638,277	'
Securities Held to Maturity, Due after five years through ten years, Amortized Cost	100,941	'
Securities Held to Maturity, Due after ten years, Amortized Cost	1,506,440	'
Securities Held to Maturity, Amortized Cost	2,250,960	2,611,352
Securities Held to Maturity, Due in one year or less, Fair Value	5,317	'
Securities Held to Maturity, Due after one year through five years, Fair Value	626,915	'
Securities Held to Maturity, Due after five years through ten years, Fair Value	99,697	'
Securities Held to Maturity, Due after ten years, Fair Value	1,521,290	'
Total Held to Maturity Securities, Fair Value	$2,253,219	$2,576,584

Securities_Available_for_Sale_

Securities - Available for Sale Securities Unrealized Losses (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	$113,252	$481,937
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	839	9,460
Available for sale securities, Losses 12 months or longer, Fair value	165,959	49,064
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	6,211	2,914
Available for sale securities, Total, Fair value	279,211	531,001
Available for sale securities, Total, Gross Unrealized Losses	7,050	12,374
Equity securities [Member]	'	'
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	'	3,282
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	'	26
Available for sale securities, Losses 12 months or longer, Fair value	3	3
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	1	1
Available for sale securities, Total, Fair value	3	3,285
Available for sale securities, Total, Gross Unrealized Losses	1	27
U.S. Treasury and government agency securities [Member]	'	'
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	163	205
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	1	1
Available for sale securities, Losses 12 months or longer, Fair value	25	'
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	'	'
Available for sale securities, Total, Fair value	188	205
Available for sale securities, Total, Gross Unrealized Losses	1	1
Municipal obligations [Member]	'	'
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	'	7,975
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	'	25
Available for sale securities, Losses 12 months or longer, Fair value	'	'
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	'	'
Available for sale securities, Total, Fair value	'	7,975
Available for sale securities, Total, Gross Unrealized Losses	'	25
Mortgage-backed securities [Member]	'	'
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	64,485	376,350
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	514	7,164
Available for sale securities, Losses 12 months or longer, Fair value	125,977	49,061
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	4,811	2,913
Available for sale securities, Total, Fair value	190,462	425,411
Available for sale securities, Total, Gross Unrealized Losses	5,325	10,077
Collateralized mortgage obligations [Member]	'	'
Unrealized Loss And Fair Value Available For Sale Securities [Line Items]	'	'
Available for sale securities, Losses less than 12 months, Fair Value	48,604	94,125
Available for sale securities, Losses Less than 12 months, Gross Unrealized Losses	324	2,244
Available for sale securities, Losses 12 months or longer, Fair value	39,954	'
Available for sale securities, Losses 12 months or longer, Gross Unrealized Losses	1,399	'
Available for sale securities, Total, Fair value	88,558	94,125
Available for sale securities, Total, Gross Unrealized Losses	$1,723	$2,244

Securities_Held_to_Maturity_wi

Securities - Held to Maturity with Unrealized Losses (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held to maturity securities, Losses less than 12 months, Fair Value	$71,715	$2,028,848
Held to maturity securities, Losses Less than 12 months, Gross Unrealized Losses	404	36,070
Held to maturity securities, Losses 12 months or longer, Fair value	742,366	178,511
Held to maturity securities, Losses 12 months or longer, Gross Unrealized Losses	18,562	1,291
Held to maturity securities, Total, Fair value	814,081	2,207,359
Held to maturity securities, Total, Gross Unrealized Losses	18,966	37,361
Municipal obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held to maturity securities, Losses less than 12 months, Fair Value	2,812	131,499
Held to maturity securities, Losses Less than 12 months, Gross Unrealized Losses	54	6,311
Held to maturity securities, Losses 12 months or longer, Fair value	55,817	2,878
Held to maturity securities, Losses 12 months or longer, Gross Unrealized Losses	1,655	125
Held to maturity securities, Total, Fair value	58,629	134,377
Held to maturity securities, Total, Gross Unrealized Losses	1,709	6,436
Mortgage-backed securities [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held to maturity securities, Losses less than 12 months, Fair Value	'	950,288
Held to maturity securities, Losses Less than 12 months, Gross Unrealized Losses	'	4,671
Held to maturity securities, Losses 12 months or longer, Fair value	128,802	'
Held to maturity securities, Losses 12 months or longer, Gross Unrealized Losses	1,258	'
Held to maturity securities, Total, Fair value	128,802	950,288
Held to maturity securities, Total, Gross Unrealized Losses	1,258	4,671
Collateralized mortgage obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held to maturity securities, Losses less than 12 months, Fair Value	68,903	947,061
Held to maturity securities, Losses Less than 12 months, Gross Unrealized Losses	350	25,088
Held to maturity securities, Losses 12 months or longer, Fair value	557,747	175,633
Held to maturity securities, Losses 12 months or longer, Gross Unrealized Losses	15,649	1,166
Held to maturity securities, Total, Fair value	626,650	1,122,694
Held to maturity securities, Total, Gross Unrealized Losses	$15,999	$26,254

Securities_Additional_Informat

Securities - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Billions, unless otherwise specified
Amortized Cost and Fair Value Debt Securities [Abstract]	'	'
Securities pledged to secure public deposits and securities sold under agreements to repurchase	$3	$3.10

Loans_and_Allowance_for_Loan_L2

Loans and Allowance for Loan Losses - Loans, Net of Unearned Income (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loans Receivable [Line Items]	'	'
Total covered loans	$280,830	$358,666
Total loans	13,348,574	12,324,817
Commercial Non-Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total covered loans	11,171	23,390
Total loans	5,587,137	5,064,224
Construction and Land Development [Member]	'	'
Loans Receivable [Line Items]	'	'
Total covered loans	11,166	20,229
Total loans	1,095,902	915,541
Commercial Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total covered loans	41,550	53,165
Total loans	3,100,834	3,042,841
Residential Mortgages [Member]	'	'
Loans Receivable [Line Items]	'	'
Total covered loans	185,289	209,018
Total loans	1,858,490	1,720,614
Consumer [Member]	'	'
Loans Receivable [Line Items]	'	'
Total covered loans	31,654	52,864
Total loans	1,706,211	1,581,597
Originated Loans [Member]	'	'
Loans Receivable [Line Items]	'	'
Ending balance: Loans	11,285,568	9,494,132
Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Commercial non-real estate	4,806,740	4,113,837
Originated Loans [Member] | Construction and Land Development [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Construction and land development	974,442	752,381
Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Commercial real estate	2,245,855	2,022,528
Originated Loans [Member] | Residential Mortgages [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Residential mortgages	1,635,462	1,196,256
Originated Loans [Member] | Consumer [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Consumer	1,623,069	1,409,130
Acquired Loans [Member]	'	'
Loans Receivable [Line Items]	'	'
Ending balance: Loans	1,782,176	2,472,019
Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Commercial non-real estate	769,226	926,997
Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Construction and land development	110,294	142,931
Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Commercial real estate	813,429	967,148
Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Residential mortgages	37,739	315,340
Acquired Loans [Member] | Consumer [Member]	'	'
Loans Receivable [Line Items]	'	'
Total Consumer	$51,488	$119,603

Loans_and_Allowance_for_Loan_L3

Loans and Allowance for Loan Losses - Schedule of Activity in Loss Share Receivable (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Receivables [Abstract]	'	'	'	'
Balance, January 1	'	'	$113,834	$177,844
Amortization	-2,760	-590	-9,989	-590
Charge-offs, write-downs and other losses (recoveries)	'	'	-793	-190
External expenses qualifying under loss share agreement	'	'	3,325	7,918
Changes due to changes in cash flow projections	'	'	-14,569	'
Settlement of disallowed loss claims	'	'	-10,268	'
Net payments (to) from FDIC	'	'	366	-60,886
Ending balance	$81,906	$124,096	$81,906	$124,096

Loans_and_Allowance_for_Loan_L4

Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2014	Sep. 30, 2014	Aug. 31, 2014	Dec. 31, 2013
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'	'	'
Expense related to the settlement of the assessment with the FDIC	$10,300,000	'	'	'
Outstanding claims due from the FDIC, net of settlement	'	'	21,100,000	'
Interest that would have been recorded on non - accrual loans	'	1,000,000	'	'
Interest recovered on non - accrual loans	'	1,000,000	'	'
Non-accrual loans	'	83,154,000	'	99,657,000
Troubled debt restructuring	'	18,000,000	'	25,000,000
Minimum bank portfolio loan need to be reviewed	'	1,000,000	'	'
Performing [Member]	'	'	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'	'	'
Period for which payments of principal and interest are past due	'	'Less than 90 days	'	'
Troubled Debt Restructurings [Member]	'	'	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'	'	'
Non-accrual loans	'	$10,000,000	'	'

Loans_and_Allowance_for_Loan_L5

Loans and Allowance for Loan Losses - Allowance for Loan Losses by Portfolio Segment and Related Recorded Investment in Loans (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	$133,626	'	'
Ending balance: Covered Loans	280,830	'	280,830	'	358,666
Ending balance: Loans	13,348,574	'	13,348,574	'	12,324,817
Net provision for loan losses	9,468	7,569	24,122	25,404	'
Increase (Decrease) in FDIC loss share receivable	'	'	-14,569	'	'
Loans and Leases receivable, Allowance, Ending Balance	125,572	'	125,572	'	'
Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	133,626	136,171	'
Charge-offs	'	'	-30,148	-40,259	'
Recoveries	'	'	12,542	15,410	'
Net provision for loan losses	'	'	24,122	25,404	'
Increase (Decrease) in FDIC loss share receivable	'	'	-14,570	1,497	'
Loans and Leases receivable, Allowance, Ending Balance	125,572	138,223	125,572	138,223	'
Ending balance: Individually evaluated for impairment	1,318	1,945	1,318	1,945	'
Ending balance: Amounts related to acquired-impaired loans	34,633	60,339	34,633	60,339	'
Ending balance: Collectively evaluated for impairment	89,621	75,939	89,621	75,939	'
Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	13,348,574	11,734,472	13,348,574	11,734,472	'
Ending balance: Individually evaluated for impairment	33,098	51,907	33,098	51,907	'
Ending balance: Acquired-impaired loans	336,667	456,973	336,667	456,973	'
Ending balance: Collectively evaluated for impairment	12,978,809	11,225,592	12,978,809	11,225,592	'
Commercial Non-Real Estate [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	11,171	'	11,171	'	23,390
Ending balance: Loans	5,587,137	'	5,587,137	'	5,064,224
Commercial Non-Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	37,017	23,725	'
Charge-offs	'	'	-4,866	-5,880	'
Recoveries	'	'	2,585	3,471	'
Net provision for loan losses	'	'	9,650	10,036	'
Increase (Decrease) in FDIC loss share receivable	'	'	-1,507	447	'
Loans and Leases receivable, Allowance, Ending Balance	42,879	31,799	42,879	31,799	'
Ending balance: Individually evaluated for impairment	116	325	116	325	'
Ending balance: Amounts related to acquired-impaired loans	1,028	1,690	1,028	1,690	'
Ending balance: Collectively evaluated for impairment	41,735	29,784	41,735	29,784	'
Commercial Non-Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	5,587,137	4,625,315	5,587,137	4,625,315	'
Ending balance: Individually evaluated for impairment	6,513	11,090	6,513	11,090	'
Ending balance: Acquired-impaired loans	15,235	43,307	15,235	43,307	'
Ending balance: Collectively evaluated for impairment	5,565,389	4,570,918	5,565,389	4,570,918	'
Construction and Land Development [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	11,166	'	11,166	'	20,229
Ending balance: Loans	1,095,902	'	1,095,902	'	915,541
Construction and Land Development [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	8,845	17,038	'
Charge-offs	'	'	-2,965	-9,332	'
Recoveries	'	'	2,724	1,797	'
Net provision for loan losses	'	'	3,449	472	'
Increase (Decrease) in FDIC loss share receivable	'	'	-2,404	-314	'
Loans and Leases receivable, Allowance, Ending Balance	9,649	9,661	9,649	9,661	'
Ending balance: Individually evaluated for impairment	676	211	676	211	'
Ending balance: Amounts related to acquired-impaired loans	1,267	2,479	1,267	2,479	'
Ending balance: Collectively evaluated for impairment	7,706	6,971	7,706	6,971	'
Construction and Land Development [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,095,902	920,408	1,095,902	920,408	'
Ending balance: Individually evaluated for impairment	8,901	16,774	8,901	16,774	'
Ending balance: Acquired-impaired loans	30,366	38,277	30,366	38,277	'
Ending balance: Collectively evaluated for impairment	1,056,635	865,357	1,056,635	865,357	'
Commercial Real Estate [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	41,550	'	41,550	'	53,165
Ending balance: Loans	3,100,834	'	3,100,834	'	3,042,841
Commercial Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	31,612	36,392	'
Charge-offs	'	'	-6,735	-8,034	'
Recoveries	'	'	2,639	4,735	'
Net provision for loan losses	'	'	-3,299	-2,038	'
Increase (Decrease) in FDIC loss share receivable	'	'	-2,418	-732	'
Loans and Leases receivable, Allowance, Ending Balance	21,799	30,323	21,799	30,323	'
Ending balance: Individually evaluated for impairment	144	1,409	144	1,409	'
Ending balance: Amounts related to acquired-impaired loans	5,314	7,977	5,314	7,977	'
Ending balance: Collectively evaluated for impairment	16,341	20,937	16,341	20,937	'
Commercial Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	3,100,834	2,914,969	3,100,834	2,914,969	'
Ending balance: Individually evaluated for impairment	14,944	23,541	14,944	23,541	'
Ending balance: Acquired-impaired loans	68,942	85,712	68,942	85,712	'
Ending balance: Collectively evaluated for impairment	3,016,948	2,805,716	3,016,948	2,805,716	'
Residential Mortgages [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	185,289	'	185,289	'	209,018
Ending balance: Loans	1,858,490	'	1,858,490	'	1,720,614
Residential Mortgages [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	34,881	36,877	'
Charge-offs	'	'	-2,470	-2,496	'
Recoveries	'	'	502	1,004	'
Net provision for loan losses	'	'	3,386	4,787	'
Increase (Decrease) in FDIC loss share receivable	'	'	-4,873	1,261	'
Loans and Leases receivable, Allowance, Ending Balance	31,426	41,433	31,426	41,433	'
Ending balance: Individually evaluated for impairment	382	'	382	'	'
Ending balance: Amounts related to acquired-impaired loans	22,183	35,521	22,183	35,521	'
Ending balance: Collectively evaluated for impairment	8,861	5,912	8,861	5,912	'
Residential Mortgages [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,858,490	1,695,197	1,858,490	1,695,197	'
Ending balance: Individually evaluated for impairment	2,740	502	2,740	502	'
Ending balance: Acquired-impaired loans	190,327	228,881	190,327	228,881	'
Ending balance: Collectively evaluated for impairment	1,665,423	1,465,814	1,665,423	1,465,814	'
Consumer [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	31,654	'	31,654	'	52,864
Ending balance: Loans	1,706,211	'	1,706,211	'	1,581,597
Consumer [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	21,271	22,139	'
Charge-offs	'	'	-13,112	-14,517	'
Recoveries	'	'	4,092	4,403	'
Net provision for loan losses	'	'	10,936	12,147	'
Increase (Decrease) in FDIC loss share receivable	'	'	-3,368	835	'
Loans and Leases receivable, Allowance, Ending Balance	19,819	25,007	19,819	25,007	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	4,841	12,672	4,841	12,672	'
Ending balance: Collectively evaluated for impairment	14,978	12,335	14,978	12,335	'
Consumer [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,706,211	1,578,583	1,706,211	1,578,583	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	31,797	60,796	31,797	60,796	'
Ending balance: Collectively evaluated for impairment	1,674,414	1,517,787	1,674,414	1,517,787	'
Covered Loans [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	53,094	56,609	'
Charge-offs	'	'	-6,875	-8,873	'
Recoveries	'	'	3,750	3,119	'
Net provision for loan losses	'	'	-766	7,987	'
Increase (Decrease) in FDIC loss share receivable	'	'	-14,570	1,497	'
Loans and Leases receivable, Allowance, Ending Balance	34,633	60,339	34,633	60,339	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	34,633	60,339	34,633	60,339	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	280,830	392,002	280,830	392,002	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	280,830	392,002	280,830	392,002	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Commercial Non-Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	2,323	2,162	'
Charge-offs	'	'	-176	-681	'
Recoveries	'	'	467	90	'
Net provision for loan losses	'	'	-79	-328	'
Increase (Decrease) in FDIC loss share receivable	'	'	-1,507	447	'
Loans and Leases receivable, Allowance, Ending Balance	1,028	1,690	1,028	1,690	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	1,028	1,690	1,028	1,690	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Commercial Non-Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	11,171	24,340	11,171	24,340	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	11,171	24,340	11,171	24,340	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Construction and Land Development [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	2,655	5,623	'
Charge-offs	'	'	-350	-1,784	'
Recoveries	'	'	1,504	554	'
Net provision for loan losses	'	'	-138	-1,600	'
Increase (Decrease) in FDIC loss share receivable	'	'	-2,404	-314	'
Loans and Leases receivable, Allowance, Ending Balance	1,267	2,479	1,267	2,479	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	1,267	2,479	1,267	2,479	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Construction and Land Development [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	11,166	23,197	11,166	23,197	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	11,166	23,197	11,166	23,197	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Commercial Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	10,929	9,433	'
Charge-offs	'	'	-4,480	-4,316	'
Recoveries	'	'	1,408	2,395	'
Net provision for loan losses	'	'	-125	1,197	'
Increase (Decrease) in FDIC loss share receivable	'	'	-2,418	-732	'
Loans and Leases receivable, Allowance, Ending Balance	5,314	7,977	5,314	7,977	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	5,314	7,977	5,314	7,977	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Commercial Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	41,550	60,280	41,550	60,280	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	41,550	60,280	41,550	60,280	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Residential Mortgages [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	27,989	30,471	'
Charge-offs	'	'	-677	-947	'
Recoveries	'	'	1	13	'
Net provision for loan losses	'	'	-257	4,723	'
Increase (Decrease) in FDIC loss share receivable	'	'	-4,873	1,261	'
Loans and Leases receivable, Allowance, Ending Balance	22,183	35,521	22,183	35,521	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	22,183	35,521	22,183	35,521	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Residential Mortgages [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	185,289	223,494	185,289	223,494	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	185,289	223,494	185,289	223,494	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Consumer [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Loans and Leases receivable, Allowance, Beginning Balance	'	'	9,198	8,920	'
Charge-offs	'	'	-1,192	-1,145	'
Recoveries	'	'	370	67	'
Net provision for loan losses	'	'	-167	3,995	'
Increase (Decrease) in FDIC loss share receivable	'	'	-3,368	835	'
Loans and Leases receivable, Allowance, Ending Balance	4,841	12,672	4,841	12,672	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	4,841	12,672	4,841	12,672	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Covered Loans [Member] | Consumer [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Covered Loans	31,654	60,691	31,654	60,691	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	31,654	60,691	31,654	60,691	'
Ending balance: Collectively evaluated for impairment	'	'	'	'	'
Originated Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	11,285,568	'	11,285,568	'	9,494,132
Originated Loans [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	78,885	78,774	'
Charge-offs	'	'	-23,273	-31,386	'
Recoveries	'	'	8,792	12,291	'
Net provision for loan losses	'	'	17,417	17,742	'
Loans and Leases receivable, Allowance, Ending Balance	81,821	77,421	81,821	77,421	'
Ending balance: Individually evaluated for impairment	754	1,482	754	1,482	'
Ending balance: Collectively evaluated for impairment	81,067	75,939	81,067	75,939	'
Originated Loans [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	11,285,568	8,700,767	11,285,568	8,700,767	'
Ending balance: Individually evaluated for impairment	29,397	46,125	29,397	46,125	'
Ending balance: Collectively evaluated for impairment	11,256,171	8,654,642	11,256,171	8,654,642	'
Originated Loans [Member] | Commercial Non-Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	33,091	20,775	'
Charge-offs	'	'	-4,690	-5,199	'
Recoveries	'	'	2,118	3,381	'
Net provision for loan losses	'	'	3,929	11,152	'
Loans and Leases receivable, Allowance, Ending Balance	34,448	30,109	34,448	30,109	'
Ending balance: Individually evaluated for impairment	24	325	24	325	'
Ending balance: Collectively evaluated for impairment	34,424	29,784	34,424	29,784	'
Originated Loans [Member] | Commercial Non-Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	4,806,740	3,633,490	4,806,740	3,633,490	'
Ending balance: Individually evaluated for impairment	5,582	8,911	5,582	8,911	'
Ending balance: Collectively evaluated for impairment	4,801,158	3,624,579	4,801,158	3,624,579	'
Originated Loans [Member] | Construction and Land Development [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	6,180	11,415	'
Charge-offs	'	'	-2,615	-7,548	'
Recoveries	'	'	1,220	1,243	'
Net provision for loan losses	'	'	2,151	2,072	'
Loans and Leases receivable, Allowance, Ending Balance	6,936	7,182	6,936	7,182	'
Ending balance: Individually evaluated for impairment	250	211	250	211	'
Ending balance: Collectively evaluated for impairment	6,686	6,971	6,686	6,971	'
Originated Loans [Member] | Construction and Land Development [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	974,442	738,983	974,442	738,983	'
Ending balance: Individually evaluated for impairment	6,617	16,044	6,617	16,044	'
Ending balance: Collectively evaluated for impairment	967,825	722,939	967,825	722,939	'
Originated Loans [Member] | Commercial Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	20,649	26,959	'
Charge-offs	'	'	-2,255	-3,718	'
Recoveries	'	'	1,231	2,340	'
Net provision for loan losses	'	'	-3,231	-3,698	'
Loans and Leases receivable, Allowance, Ending Balance	16,394	21,883	16,394	21,883	'
Ending balance: Individually evaluated for impairment	98	946	98	946	'
Ending balance: Collectively evaluated for impairment	16,296	20,937	16,296	20,937	'
Originated Loans [Member] | Commercial Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	2,245,855	1,816,402	2,245,855	1,816,402	'
Ending balance: Individually evaluated for impairment	14,486	21,170	14,486	21,170	'
Ending balance: Collectively evaluated for impairment	2,231,369	1,795,232	2,231,369	1,795,232	'
Originated Loans [Member] | Residential Mortgages [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	6,892	6,406	'
Charge-offs	'	'	-1,793	-1,549	'
Recoveries	'	'	501	991	'
Net provision for loan losses	'	'	3,647	64	'
Loans and Leases receivable, Allowance, Ending Balance	9,247	5,912	9,247	5,912	'
Ending balance: Individually evaluated for impairment	382	'	382	'	'
Ending balance: Collectively evaluated for impairment	8,865	5,912	8,865	5,912	'
Originated Loans [Member] | Residential Mortgages [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,635,462	1,124,649	1,635,462	1,124,649	'
Ending balance: Individually evaluated for impairment	2,712	'	2,712	'	'
Ending balance: Collectively evaluated for impairment	1,632,750	1,124,649	1,632,750	1,124,649	'
Originated Loans [Member] | Consumer [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	12,073	13,219	'
Charge-offs	'	'	-11,920	-13,372	'
Recoveries	'	'	3,722	4,336	'
Net provision for loan losses	'	'	10,921	8,152	'
Loans and Leases receivable, Allowance, Ending Balance	14,796	12,335	14,796	12,335	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	14,796	12,335	14,796	12,335	'
Originated Loans [Member] | Consumer [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,623,069	1,387,243	1,623,069	1,387,243	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	1,623,069	1,387,243	1,623,069	1,387,243	'
Acquired Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,782,176	'	1,782,176	'	2,472,019
Acquired Loans [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	1,647	788	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	7,471	-325	'
Loans and Leases receivable, Allowance, Ending Balance	9,118	463	9,118	463	'
Ending balance: Individually evaluated for impairment	564	463	564	463	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	8,554	'	8,554	'	'
Acquired Loans [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	1,782,176	2,641,703	1,782,176	2,641,703	'
Ending balance: Individually evaluated for impairment	3,701	5,782	3,701	5,782	'
Ending balance: Acquired-impaired loans	55,837	64,971	55,837	64,971	'
Ending balance: Collectively evaluated for impairment	1,722,638	2,570,950	1,722,638	2,570,950	'
Acquired Loans [Member] | Commercial Non-Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	1,603	788	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	5,800	-788	'
Loans and Leases receivable, Allowance, Ending Balance	7,403	'	7,403	'	'
Ending balance: Individually evaluated for impairment	92	'	92	'	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	7,311	'	7,311	'	'
Acquired Loans [Member] | Commercial Non-Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	769,226	967,485	769,226	967,485	'
Ending balance: Individually evaluated for impairment	931	2,179	931	2,179	'
Ending balance: Acquired-impaired loans	4,064	18,967	4,064	18,967	'
Ending balance: Collectively evaluated for impairment	764,231	946,339	764,231	946,339	'
Acquired Loans [Member] | Construction and Land Development [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	10	'	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	1,436	'	'
Loans and Leases receivable, Allowance, Ending Balance	1,446	'	1,446	'	'
Ending balance: Individually evaluated for impairment	426	'	426	'	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	1,020	'	1,020	'	'
Acquired Loans [Member] | Construction and Land Development [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	110,294	158,228	110,294	158,228	'
Ending balance: Individually evaluated for impairment	2,284	730	2,284	730	'
Ending balance: Acquired-impaired loans	19,200	15,080	19,200	15,080	'
Ending balance: Collectively evaluated for impairment	88,810	142,418	88,810	142,418	'
Acquired Loans [Member] | Commercial Real Estate [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	34	'	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	57	463	'
Loans and Leases receivable, Allowance, Ending Balance	91	463	91	463	'
Ending balance: Individually evaluated for impairment	46	463	46	463	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	45	'	45	'	'
Acquired Loans [Member] | Commercial Real Estate [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	813,429	1,038,287	813,429	1,038,287	'
Ending balance: Individually evaluated for impairment	458	2,371	458	2,371	'
Ending balance: Acquired-impaired loans	27,392	25,432	27,392	25,432	'
Ending balance: Collectively evaluated for impairment	785,579	1,010,484	785,579	1,010,484	'
Acquired Loans [Member] | Residential Mortgages [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	'	'	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	-4	'	'
Loans and Leases receivable, Allowance, Ending Balance	-4	'	-4	'	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	-4	'	-4	'	'
Acquired Loans [Member] | Residential Mortgages [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	37,739	347,054	37,739	347,054	'
Ending balance: Individually evaluated for impairment	28	502	28	502	'
Ending balance: Acquired-impaired loans	5,038	5,387	5,038	5,387	'
Ending balance: Collectively evaluated for impairment	32,673	341,165	32,673	341,165	'
Acquired Loans [Member] | Consumer [Member] | Allowance for loan losses [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Beginning balance	'	'	'	'	'
Charge-offs	'	'	'	'	'
Recoveries	'	'	'	'	'
Net provision for loan losses	'	'	182	'	'
Loans and Leases receivable, Allowance, Ending Balance	182	'	182	'	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Amounts related to acquired-impaired loans	'	'	'	'	'
Ending balance: Collectively evaluated for impairment	182	'	182	'	'
Acquired Loans [Member] | Consumer [Member] | Loans [Member]	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'
Ending balance: Loans	51,488	130,649	51,488	130,649	'
Ending balance: Individually evaluated for impairment	'	'	'	'	'
Ending balance: Acquired-impaired loans	143	105	143	105	'
Ending balance: Collectively evaluated for impairment	$51,345	$130,544	$51,345	$130,544	'

Loans_and_Allowance_for_Loan_L6

Loans and Allowance for Loan Losses - Summary of Composition of Non-Accrual Loans by Portfolio Segment (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	$83,154	$99,657
Commercial Non-Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	11,136	13,330
Construction and Land Development [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	10,897	16,700
Commercial Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	31,749	40,460
Residential Mortgages [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	23,073	22,255
Consumer [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	6,299	6,912
Originated Loans [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	68,362	74,313
Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	9,279	10,119
Originated Loans [Member] | Construction and Land Development [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	6,083	13,171
Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	26,432	32,772
Originated Loans [Member] | Residential Mortgages [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	21,326	13,449
Originated Loans [Member] | Consumer [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	5,242	4,802
Acquired Loans [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	11,572	21,800
Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	1,857	3,209
Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	3,275	1,990
Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	4,210	6,525
Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	1,353	8,262
Acquired Loans [Member] | Consumer [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	877	1,814
Covered Loans [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	3,220	3,544
Covered Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	'	2
Covered Loans [Member] | Construction and Land Development [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	1,539	1,539
Covered Loans [Member] | Commercial Real Estate [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	1,107	1,163
Covered Loans [Member] | Residential Mortgages [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	394	544
Covered Loans [Member] | Consumer [Member]	'	'
Nonaccrual Loans By Portfolio [Line Items]	'	'
Non-accrual loans	$180	$296

Loans_and_Allowance_for_Loan_L7

Loans and Allowance for Loan Losses - Schedule of Troubled Debt Restructurings Occurred During Period by Portfolio Segment (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
	Contract	Contract
Troubled Debt Restructurings [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	6	10
Pre-Modification Outstanding Recorded Investment	$3,925	$4,767
Post-Modification Outstanding Recorded Investment	3,233	4,557
Troubled Debt Restructurings [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	1
Pre-Modification Outstanding Recorded Investment	'	925
Post-Modification Outstanding Recorded Investment	'	920
Troubled Debt Restructurings [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	2	6
Pre-Modification Outstanding Recorded Investment	2,430	2,356
Post-Modification Outstanding Recorded Investment	2,385	2,290
Troubled Debt Restructurings [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	4	3
Pre-Modification Outstanding Recorded Investment	1,495	1,486
Post-Modification Outstanding Recorded Investment	848	1,347
Troubled Debt Restructurings [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Originated Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	6	8
Pre-Modification Outstanding Recorded Investment	3,925	3,740
Post-Modification Outstanding Recorded Investment	3,233	3,563
Troubled Debt Restructurings [Member] | Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	1
Pre-Modification Outstanding Recorded Investment	'	925
Post-Modification Outstanding Recorded Investment	'	920
Troubled Debt Restructurings [Member] | Originated Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	2	5
Pre-Modification Outstanding Recorded Investment	2,430	1,844
Post-Modification Outstanding Recorded Investment	2,385	1,789
Troubled Debt Restructurings [Member] | Originated Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	4	2
Pre-Modification Outstanding Recorded Investment	1,495	971
Post-Modification Outstanding Recorded Investment	848	854
Troubled Debt Restructurings [Member] | Originated Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Acquired Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	2
Pre-Modification Outstanding Recorded Investment	'	1,027
Post-Modification Outstanding Recorded Investment	'	994
Troubled Debt Restructurings [Member] | Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	1
Pre-Modification Outstanding Recorded Investment	'	512
Post-Modification Outstanding Recorded Investment	'	501
Troubled Debt Restructurings [Member] | Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	1
Pre-Modification Outstanding Recorded Investment	'	515
Post-Modification Outstanding Recorded Investment	'	493
Troubled Debt Restructurings [Member] | Acquired Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings [Member] | Covered Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Pre-Modification Outstanding Recorded Investment	'	'
Post-Modification Outstanding Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	1	'
Recorded Investment	909	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	1	'
Recorded Investment	909	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	1	'
Recorded Investment	909	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	1	'
Recorded Investment	909	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Originated Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Acquired Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member] | Construction and Land Development [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member] | Commercial Real Estate [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member] | Residential Mortgages [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'
Troubled Debt Restructurings That Subsequently Defaulted [Member] | Covered Loans [Member] | Consumer [Member]	'	'
Troubled Debt Restructuring, Debtor, Current Period [Line Items]	'	'
Number of Contracts	'	'
Recorded Investment	'	'

Loans_and_Allowance_for_Loan_L8

Loans and Allowance for Loan Losses - Summary of Impaired Loans Disaggregated by Class (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	$15,611	$14,958
Recorded Investment, With a related allowance recorded	17,487	20,776
Recorded Investment, Total	33,098	35,734
Unpaid Principal Balance, With no related allowance recorded	23,026	20,589
Unpaid Principal Balance, With a related allowance recorded	21,448	23,356
Unpaid Principal Balance, Total	44,474	43,945
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	1,318	768
Related Allowance, Total	1,318	768
Average Recorded Investment, With no related allowance recorded	13,768	23,083
Average Recorded Investment, With a related allowance recorded	25,845	38,833
Average Recorded Investment, Total	39,613	61,916
Interest Income Recognized, With no related allowance recorded	390	534
Interest Income Recognized, With a related allowance recorded	504	703
Interest Income Recognized, Total	894	1,237
Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	1,498	2,470
Recorded Investment, With a related allowance recorded	5,015	4,965
Recorded Investment, Total	6,513	7,435
Unpaid Principal Balance, With no related allowance recorded	3,841	3,717
Unpaid Principal Balance, With a related allowance recorded	5,243	5,303
Unpaid Principal Balance, Total	9,084	9,020
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	116	477
Related Allowance, Total	116	477
Average Recorded Investment, With no related allowance recorded	1,514	1,100
Average Recorded Investment, With a related allowance recorded	7,226	11,683
Average Recorded Investment, Total	8,740	12,783
Interest Income Recognized, With no related allowance recorded	31	26
Interest Income Recognized, With a related allowance recorded	195	243
Interest Income Recognized, Total	226	269
Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	3,320	4,829
Recorded Investment, With a related allowance recorded	5,581	6,498
Recorded Investment, Total	8,901	11,327
Unpaid Principal Balance, With no related allowance recorded	5,459	6,273
Unpaid Principal Balance, With a related allowance recorded	8,650	8,343
Unpaid Principal Balance, Total	14,109	14,616
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	676	22
Related Allowance, Total	676	22
Average Recorded Investment, With no related allowance recorded	3,339	3,076
Average Recorded Investment, With a related allowance recorded	7,708	2,706
Average Recorded Investment, Total	11,047	5,782
Interest Income Recognized, With no related allowance recorded	112	85
Interest Income Recognized, With a related allowance recorded	145	'
Interest Income Recognized, Total	257	85
Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	10,502	7,186
Recorded Investment, With a related allowance recorded	4,442	8,708
Recorded Investment, Total	14,944	15,894
Unpaid Principal Balance, With no related allowance recorded	13,011	10,092
Unpaid Principal Balance, With a related allowance recorded	4,797	9,090
Unpaid Principal Balance, Total	17,808	19,182
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	144	268
Related Allowance, Total	144	268
Average Recorded Investment, With no related allowance recorded	8,739	17,225
Average Recorded Investment, With a related allowance recorded	8,722	22,346
Average Recorded Investment, Total	17,461	39,571
Interest Income Recognized, With no related allowance recorded	246	423
Interest Income Recognized, With a related allowance recorded	136	460
Interest Income Recognized, Total	382	883
Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	291	473
Recorded Investment, With a related allowance recorded	2,449	605
Recorded Investment, Total	2,740	1,078
Unpaid Principal Balance, With no related allowance recorded	715	507
Unpaid Principal Balance, With a related allowance recorded	2,758	620
Unpaid Principal Balance, Total	3,473	1,127
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	382	1
Related Allowance, Total	382	1
Average Recorded Investment, With no related allowance recorded	176	669
Average Recorded Investment, With a related allowance recorded	2,189	1,073
Average Recorded Investment, Total	2,365	1,742
Interest Income Recognized, With no related allowance recorded	1	'
Interest Income Recognized, With a related allowance recorded	28	'
Interest Income Recognized, Total	29	'
Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	1,013
Average Recorded Investment, With a related allowance recorded	'	1,025
Average Recorded Investment, Total	'	2,038
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	15,583	9,751
Recorded Investment, With a related allowance recorded	13,814	20,776
Recorded Investment, Total	29,397	30,527
Unpaid Principal Balance, With no related allowance recorded	21,228	13,031
Unpaid Principal Balance, With a related allowance recorded	15,050	23,356
Unpaid Principal Balance, Total	36,278	36,387
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	754	768
Related Allowance, Total	754	768
Average Recorded Investment, With no related allowance recorded	12,891	20,176
Average Recorded Investment, With a related allowance recorded	22,106	32,421
Average Recorded Investment, Total	34,997	52,597
Interest Income Recognized, With no related allowance recorded	390	474
Interest Income Recognized, With a related allowance recorded	280	640
Interest Income Recognized, Total	670	1,114
Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	1,498	329
Recorded Investment, With a related allowance recorded	4,084	4,965
Recorded Investment, Total	5,582	5,294
Unpaid Principal Balance, With no related allowance recorded	2,111	442
Unpaid Principal Balance, With a related allowance recorded	4,173	5,303
Unpaid Principal Balance, Total	6,284	5,745
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	24	477
Related Allowance, Total	24	477
Average Recorded Investment, With no related allowance recorded	1,157	235
Average Recorded Investment, With a related allowance recorded	5,922	8,936
Average Recorded Investment, Total	7,079	9,171
Interest Income Recognized, With no related allowance recorded	31	18
Interest Income Recognized, With a related allowance recorded	77	180
Interest Income Recognized, Total	108	198
Originated Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	3,320	4,101
Recorded Investment, With a related allowance recorded	3,297	6,498
Recorded Investment, Total	6,617	10,599
Unpaid Principal Balance, With no related allowance recorded	5,459	5,131
Unpaid Principal Balance, With a related allowance recorded	3,815	8,343
Unpaid Principal Balance, Total	9,274	13,474
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	250	22
Related Allowance, Total	250	22
Average Recorded Investment, With no related allowance recorded	3,218	2,780
Average Recorded Investment, With a related allowance recorded	6,578	2,549
Average Recorded Investment, Total	9,796	5,329
Interest Income Recognized, With no related allowance recorded	112	82
Interest Income Recognized, With a related allowance recorded	100	'
Interest Income Recognized, Total	212	82
Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	10,502	5,321
Recorded Investment, With a related allowance recorded	3,984	8,708
Recorded Investment, Total	14,486	14,029
Unpaid Principal Balance, With no related allowance recorded	13,011	7,458
Unpaid Principal Balance, With a related allowance recorded	4,304	9,090
Unpaid Principal Balance, Total	17,315	16,548
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	98	268
Related Allowance, Total	98	268
Average Recorded Investment, With no related allowance recorded	8,428	15,886
Average Recorded Investment, With a related allowance recorded	7,417	19,683
Average Recorded Investment, Total	15,845	35,569
Interest Income Recognized, With no related allowance recorded	246	374
Interest Income Recognized, With a related allowance recorded	75	460
Interest Income Recognized, Total	321	834
Originated Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	263	'
Recorded Investment, With a related allowance recorded	2,449	605
Recorded Investment, Total	2,712	605
Unpaid Principal Balance, With no related allowance recorded	647	'
Unpaid Principal Balance, With a related allowance recorded	2,758	620
Unpaid Principal Balance, Total	3,405	620
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	382	1
Related Allowance, Total	382	1
Average Recorded Investment, With no related allowance recorded	88	262
Average Recorded Investment, With a related allowance recorded	2,189	228
Average Recorded Investment, Total	2,277	490
Interest Income Recognized, With no related allowance recorded	1	'
Interest Income Recognized, With a related allowance recorded	28	'
Interest Income Recognized, Total	29	'
Originated Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	1,013
Average Recorded Investment, With a related allowance recorded	'	1,025
Average Recorded Investment, Total	'	2,038
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	28	5,207
Recorded Investment, With a related allowance recorded	3,673	'
Recorded Investment, Total	3,701	5,207
Unpaid Principal Balance, With no related allowance recorded	1,798	7,558
Unpaid Principal Balance, With a related allowance recorded	6,398	'
Unpaid Principal Balance, Total	8,196	7,558
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	564	'
Related Allowance, Total	564	'
Average Recorded Investment, With no related allowance recorded	877	2,907
Average Recorded Investment, With a related allowance recorded	3,739	6,412
Average Recorded Investment, Total	4,616	9,319
Interest Income Recognized, With no related allowance recorded	'	60
Interest Income Recognized, With a related allowance recorded	224	63
Interest Income Recognized, Total	224	123
Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	2,141
Recorded Investment, With a related allowance recorded	931	'
Recorded Investment, Total	931	2,141
Unpaid Principal Balance, With no related allowance recorded	1,730	3,275
Unpaid Principal Balance, With a related allowance recorded	1,070	'
Unpaid Principal Balance, Total	2,800	3,275
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	92	'
Related Allowance, Total	92	'
Average Recorded Investment, With no related allowance recorded	357	865
Average Recorded Investment, With a related allowance recorded	1,304	2,747
Average Recorded Investment, Total	1,661	3,612
Interest Income Recognized, With no related allowance recorded	'	8
Interest Income Recognized, With a related allowance recorded	118	63
Interest Income Recognized, Total	118	71
Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	728
Recorded Investment, With a related allowance recorded	2,284	'
Recorded Investment, Total	2,284	728
Unpaid Principal Balance, With no related allowance recorded	'	1,142
Unpaid Principal Balance, With a related allowance recorded	4,835	'
Unpaid Principal Balance, Total	4,835	1,142
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	426	'
Related Allowance, Total	426	'
Average Recorded Investment, With no related allowance recorded	121	296
Average Recorded Investment, With a related allowance recorded	1,130	157
Average Recorded Investment, Total	1,251	453
Interest Income Recognized, With no related allowance recorded	'	3
Interest Income Recognized, With a related allowance recorded	45	'
Interest Income Recognized, Total	45	3
Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	1,865
Recorded Investment, With a related allowance recorded	458	'
Recorded Investment, Total	458	1,865
Unpaid Principal Balance, With no related allowance recorded	'	2,634
Unpaid Principal Balance, With a related allowance recorded	493	'
Unpaid Principal Balance, Total	493	2,634
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	46	'
Related Allowance, Total	46	'
Average Recorded Investment, With no related allowance recorded	311	1,339
Average Recorded Investment, With a related allowance recorded	1,305	2,663
Average Recorded Investment, Total	1,616	4,002
Interest Income Recognized, With no related allowance recorded	'	49
Interest Income Recognized, With a related allowance recorded	61	'
Interest Income Recognized, Total	61	49
Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	28	473
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	28	473
Unpaid Principal Balance, With no related allowance recorded	68	507
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	68	507
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	88	407
Average Recorded Investment, With a related allowance recorded	'	845
Average Recorded Investment, Total	88	1,252
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Acquired Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'
Covered Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Recorded Investment, With no related allowance recorded	'	'
Recorded Investment, With a related allowance recorded	'	'
Recorded Investment, Total	'	'
Unpaid Principal Balance, With no related allowance recorded	'	'
Unpaid Principal Balance, With a related allowance recorded	'	'
Unpaid Principal Balance, Total	'	'
Related Allowance, With no related allowance recorded	'	'
Related Allowance, With a related allowance recorded	'	'
Related Allowance, Total	'	'
Average Recorded Investment, With no related allowance recorded	'	'
Average Recorded Investment, With a related allowance recorded	'	'
Average Recorded Investment, Total	'	'
Interest Income Recognized, With no related allowance recorded	'	'
Interest Income Recognized, With a related allowance recorded	'	'
Interest Income Recognized, Total	'	'

Loans_and_Allowance_for_Loan_L9

Loans and Allowance for Loan Losses - Summary of Age Analysis of Past Due Loans (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	$280,830	$358,666
Total loans	13,348,574	12,324,817
30-59 days past due	15,255	60,155
60-89 days past due	17,262	22,018
Greater than 90 days past due	43,884	53,143
Total past due	76,401	135,316
Current	13,272,173	12,189,501
Recorded investment > 90 days and accruing	6,667	10,374
Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	11,171	23,390
Total loans	5,587,137	5,064,224
30-59 days past due	4,288	13,627
60-89 days past due	4,134	3,535
Greater than 90 days past due	4,845	6,270
Total past due	13,267	23,432
Current	5,573,870	5,040,792
Recorded investment > 90 days and accruing	259	1,062
Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	11,166	20,229
Total loans	1,095,902	915,541
30-59 days past due	1,390	6,739
60-89 days past due	2,300	2,793
Greater than 90 days past due	7,585	8,670
Total past due	11,275	18,202
Current	1,084,627	897,339
Recorded investment > 90 days and accruing	1,460	541
Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	41,550	53,165
Total loans	3,100,834	3,042,841
30-59 days past due	4,046	11,920
60-89 days past due	2,811	7,089
Greater than 90 days past due	15,805	24,321
Total past due	22,662	43,330
Current	3,078,172	2,999,511
Recorded investment > 90 days and accruing	1,728	6,273
Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	185,289	209,018
Total loans	1,858,490	1,720,614
30-59 days past due	633	18,042
60-89 days past due	5,220	6,568
Greater than 90 days past due	10,731	9,046
Total past due	16,584	33,656
Current	1,841,906	1,686,958
Recorded investment > 90 days and accruing	220	72
Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total covered loans	31,654	52,864
Total loans	1,706,211	1,581,597
30-59 days past due	4,898	9,827
60-89 days past due	2,797	2,033
Greater than 90 days past due	4,918	4,836
Total past due	12,613	16,696
Current	1,693,598	1,564,901
Recorded investment > 90 days and accruing	3,000	2,426
Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered	11,285,568	9,494,132
30-59 days past due	13,965	46,908
60-89 days past due	14,487	13,994
Greater than 90 days past due	36,360	32,756
Total past due	64,812	93,658
Current	11,220,756	9,400,474
Recorded investment > 90 days and accruing	5,149	3,285
Originated Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Commercial non-real estate	4,806,740	4,113,837
30-59 days past due	4,137	11,645
60-89 days past due	4,039	1,203
Greater than 90 days past due	3,111	4,803
Total past due	11,287	17,651
Current	4,795,453	4,096,186
Recorded investment > 90 days and accruing	259	521
Originated Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Construction and land development	974,442	752,381
30-59 days past due	1,159	5,877
60-89 days past due	651	1,264
Greater than 90 days past due	6,185	5,970
Total past due	7,995	13,111
Current	966,447	739,270
Recorded investment > 90 days and accruing	1,443	'
Originated Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Commercial real estate	2,245,855	2,022,528
30-59 days past due	3,524	8,178
60-89 days past due	2,170	5,744
Greater than 90 days past due	12,271	14,620
Total past due	17,965	28,542
Current	2,227,890	1,993,986
Recorded investment > 90 days and accruing	257	420
Originated Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Residential mortgages	1,635,462	1,196,256
30-59 days past due	606	12,410
60-89 days past due	5,071	3,870
Greater than 90 days past due	10,503	3,540
Total past due	16,180	19,820
Current	1,619,282	1,176,436
Recorded investment > 90 days and accruing	220	'
Originated Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Consumer	1,623,069	1,409,130
30-59 days past due	4,539	8,798
60-89 days past due	2,556	1,913
Greater than 90 days past due	4,290	3,823
Total past due	11,385	14,534
Current	1,611,684	1,394,596
Recorded investment > 90 days and accruing	2,970	2,344
Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered	1,782,176	2,472,019
30-59 days past due	1,289	13,247
60-89 days past due	2,626	8,024
Greater than 90 days past due	7,489	18,170
Total past due	11,404	39,441
Current	1,770,772	2,432,578
Recorded investment > 90 days and accruing	1,518	7,089
Acquired Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Commercial non-real estate	769,226	926,997
30-59 days past due	151	1,982
60-89 days past due	95	2,332
Greater than 90 days past due	1,734	1,467
Total past due	1,980	5,781
Current	767,246	921,216
Recorded investment > 90 days and accruing	'	541
Acquired Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Construction and land development	110,294	142,931
30-59 days past due	231	862
60-89 days past due	1,649	1,529
Greater than 90 days past due	1,400	1,161
Total past due	3,280	3,552
Current	107,014	139,379
Recorded investment > 90 days and accruing	17	541
Acquired Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Commercial real estate	813,429	967,148
30-59 days past due	522	3,742
60-89 days past due	641	1,345
Greater than 90 days past due	3,534	9,026
Total past due	4,697	14,113
Current	808,732	953,035
Recorded investment > 90 days and accruing	1,471	5,853
Acquired Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Residential mortgages	37,739	315,340
30-59 days past due	27	5,632
60-89 days past due	'	2,698
Greater than 90 days past due	228	5,503
Total past due	255	13,833
Current	37,484	301,507
Recorded investment > 90 days and accruing	'	72
Acquired Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total-excluding covered-Consumer	51,488	119,603
30-59 days past due	358	1,029
60-89 days past due	241	120
Greater than 90 days past due	593	1,013
Total past due	1,192	2,162
Current	50,296	117,441
Recorded investment > 90 days and accruing	30	82
Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	1	'
60-89 days past due	149	'
Greater than 90 days past due	35	2,217
Total past due	185	2,217
Current	280,645	356,449
Recorded investment > 90 days and accruing	'	'
Covered Loans [Member] | Commercial Non-Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	'	'
60-89 days past due	'	'
Greater than 90 days past due	'	'
Total past due	'	'
Current	11,171	23,390
Recorded investment > 90 days and accruing	'	'
Covered Loans [Member] | Construction and Land Development [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	'	'
60-89 days past due	'	'
Greater than 90 days past due	'	1,539
Total past due	'	1,539
Current	11,166	18,690
Recorded investment > 90 days and accruing	'	'
Covered Loans [Member] | Commercial Real Estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	'	'
60-89 days past due	'	'
Greater than 90 days past due	'	675
Total past due	'	675
Current	41,550	52,490
Covered Loans [Member] | Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	'	'
60-89 days past due	149	'
Greater than 90 days past due	'	3
Total past due	149	3
Current	185,140	209,015
Recorded investment > 90 days and accruing	'	'
Covered Loans [Member] | Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
30-59 days past due	1	'
60-89 days past due	'	'
Greater than 90 days past due	35	'
Total past due	36	'
Current	31,618	52,864
Recorded investment > 90 days and accruing	'	'

Recovered_Sheet1

Loans and Allowance for Loan Losses - Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile Based on Payment Activity (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Commercial Non Real Estate Credit Exposure [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	$5,587,137	$5,064,224
Commercial Non Real Estate Credit Exposure [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	4,806,740	4,113,837
Commercial Non Real Estate Credit Exposure [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	769,226	926,997
Commercial Non Real Estate Credit Exposure [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	11,171	23,390
Commercial Non Real Estate Credit Exposure [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	5,356,866	4,846,931
Commercial Non Real Estate Credit Exposure [Member] | Pass [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	4,656,899	3,990,320
Commercial Non Real Estate Credit Exposure [Member] | Pass [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	698,111	846,134
Commercial Non Real Estate Credit Exposure [Member] | Pass [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,856	10,477
Commercial Non Real Estate Credit Exposure [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	91,266	90,848
Commercial Non Real Estate Credit Exposure [Member] | Pass-Watch [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	58,894	46,734
Commercial Non Real Estate Credit Exposure [Member] | Pass-Watch [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	32,372	44,105
Commercial Non Real Estate Credit Exposure [Member] | Pass-Watch [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	9
Commercial Non Real Estate Credit Exposure [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	54,025	64,624
Commercial Non Real Estate Credit Exposure [Member] | Special Mention [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	26,869	41,812
Commercial Non Real Estate Credit Exposure [Member] | Special Mention [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	26,635	19,915
Commercial Non Real Estate Credit Exposure [Member] | Special Mention [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	521	2,897
Commercial Non Real Estate Credit Exposure [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	84,861	60,063
Commercial Non Real Estate Credit Exposure [Member] | Substandard [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	63,959	34,276
Commercial Non Real Estate Credit Exposure [Member] | Substandard [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	12,108	16,125
Commercial Non Real Estate Credit Exposure [Member] | Substandard [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	8,794	9,662
Commercial Non Real Estate Credit Exposure [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	119	1,758
Commercial Non Real Estate Credit Exposure [Member] | Doubtful [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	119	695
Commercial Non Real Estate Credit Exposure [Member] | Doubtful [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	718
Commercial Non Real Estate Credit Exposure [Member] | Doubtful [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	345
Commercial Non Real Estate Credit Exposure [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Commercial Non Real Estate Credit Exposure [Member] | Loss [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Commercial Non Real Estate Credit Exposure [Member] | Loss [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Commercial Non Real Estate Credit Exposure [Member] | Loss [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,095,902	915,541
Construction Credit Exposure [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	974,442	752,381
Construction Credit Exposure [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	110,294	142,931
Construction Credit Exposure [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	11,166	20,229
Construction Credit Exposure [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,008,190	822,035
Construction Credit Exposure [Member] | Pass [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	923,800	709,261
Construction Credit Exposure [Member] | Pass [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	82,067	112,773
Construction Credit Exposure [Member] | Pass [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	2,323	1
Construction Credit Exposure [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	21,487	10,950
Construction Credit Exposure [Member] | Pass-Watch [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	17,576	7,817
Construction Credit Exposure [Member] | Pass-Watch [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	2,911	1,907
Construction Credit Exposure [Member] | Pass-Watch [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,000	1,226
Construction Credit Exposure [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	11,598	13,611
Construction Credit Exposure [Member] | Special Mention [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	5,832	3,926
Construction Credit Exposure [Member] | Special Mention [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	5,737	9,409
Construction Credit Exposure [Member] | Special Mention [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	29	276
Construction Credit Exposure [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	54,627	61,717
Construction Credit Exposure [Member] | Substandard [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	27,234	31,377
Construction Credit Exposure [Member] | Substandard [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	19,579	18,842
Construction Credit Exposure [Member] | Substandard [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	7,814	11,498
Construction Credit Exposure [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	7,228
Construction Credit Exposure [Member] | Doubtful [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member] | Doubtful [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member] | Doubtful [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	7,228
Construction Credit Exposure [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member] | Loss [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member] | Loss [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Construction Credit Exposure [Member] | Loss [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	'	'
Consumer [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,706,211	1,581,597
Consumer [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,623,069	1,409,130
Consumer [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	51,488	119,603
Consumer [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	31,654	52,864
Consumer [Member] | Performing [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,701,293	1,574,685
Consumer [Member] | Performing [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	1,618,779	1,404,032
Consumer [Member] | Performing [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	50,895	117,789
Consumer [Member] | Performing [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	31,619	52,864
Consumer [Member] | Nonperforming [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	4,918	6,912
Consumer [Member] | Nonperforming [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	4,290	5,098
Consumer [Member] | Nonperforming [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	593	1,814
Consumer [Member] | Nonperforming [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile based on payment activity	$35	'

Recovered_Sheet2

Loans and Allowance for Loan Losses - Schedule of Credit Quality Indicators of Various Classes of Loans - Credit Risk Profile by Internally Assigned Grade (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Commercial Real Estate Credit Exposure [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	$3,100,834	$3,042,841
Commercial Real Estate Credit Exposure [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	2,813,783	2,762,371
Commercial Real Estate Credit Exposure [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	98,265	69,374
Commercial Real Estate Credit Exposure [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	35,734	37,582
Commercial Real Estate Credit Exposure [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	152,991	165,626
Commercial Real Estate Credit Exposure [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	61	7,888
Commercial Real Estate Credit Exposure [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	'
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	2,245,855	2,022,528
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	2,048,886	1,864,115
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	83,729	49,578
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	25,842	15,785
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	87,369	93,034
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	29	16
Commercial Real Estate Credit Exposure [Member] | Originated Loans [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	'
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	813,429	967,148
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	758,092	896,578
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	8,725	9,530
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	9,029	19,798
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	37,583	41,242
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	'
Commercial Real Estate Credit Exposure [Member] | Acquired Loans [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	'
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	41,550	53,165
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Pass [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	6,805	1,678
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Pass-Watch [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	5,811	10,266
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Special Mention [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	863	1,999
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Substandard [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	28,039	31,350
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Doubtful [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	32	7,872
Commercial Real Estate Credit Exposure [Member] | Covered Loans [Member] | Loss [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	'
Residential Mortgages [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	1,858,490	1,720,614
Residential Mortgages [Member] | Performing [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	1,847,759	1,698,359
Residential Mortgages [Member] | Nonperforming [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	10,731	22,255
Residential Mortgages [Member] | Originated Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	1,635,462	1,196,256
Residential Mortgages [Member] | Originated Loans [Member] | Performing [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	1,624,959	1,182,266
Residential Mortgages [Member] | Originated Loans [Member] | Nonperforming [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	10,503	13,990
Residential Mortgages [Member] | Acquired Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	37,739	315,340
Residential Mortgages [Member] | Acquired Loans [Member] | Performing [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	37,511	307,078
Residential Mortgages [Member] | Acquired Loans [Member] | Nonperforming [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	228	8,262
Residential Mortgages [Member] | Covered Loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	185,289	209,018
Residential Mortgages [Member] | Covered Loans [Member] | Performing [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	185,289	209,015
Residential Mortgages [Member] | Covered Loans [Member] | Nonperforming [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Credit risk profile by internally assigned grade	'	$3

Recovered_Sheet3

Loans and Allowance for Loan Losses - Changes in Carrying Amount of Covered Acquired Loans and Accretable Yield for Loans Receivable (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Covered Loans [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Carrying Amount of Loans, Balance at beginning of period	$358,666	$515,823
Carrying Amount of Loans, Additions	'	'
Carrying Amount of Loans, Payments received, net	-92,890	-189,987
Carrying Amount of Loans, Accretion	15,054	32,830
Carrying Amount of Loans, Balance at end of period	280,830	358,666
Accretable Yield, Balance at beginning of period	122,715	115,594
Accretable Yield, Additions	'	'
Accretable Yield, Payments received, net	-953	-1,298
Accretable Yield, Accretion	-15,054	-32,830
Accretable Yield, Increase (Decrease) in expected cash flows based on actual cash flows and changes in cash flow assumptions	1,783	-17,433
Net transfers from nonaccretable difference to accretable yield	11,917	58,682
Accretable Yield, Balance at end of period	120,408	122,715
Non-Covered [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Carrying Amount of Loans, Balance at beginning of period	68,075	141,201
Carrying Amount of Loans, Additions	'	'
Carrying Amount of Loans, Payments received, net	-47,979	-116,187
Carrying Amount of Loans, Accretion	35,741	43,061
Carrying Amount of Loans, Balance at end of period	55,837	68,075
Accretable Yield, Balance at beginning of period	131,370	203,186
Accretable Yield, Additions	'	'
Accretable Yield, Payments received, net	-28,487	-47,330
Accretable Yield, Accretion	-35,741	-43,061
Accretable Yield, Increase (Decrease) in expected cash flows based on actual cash flows and changes in cash flow assumptions	-380	3,894
Net transfers from nonaccretable difference to accretable yield	19,076	14,681
Accretable Yield, Balance at end of period	$85,838	$131,370

Fair_Value_Schedule_of_Financi

Fair Value - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	$1,662,410	$1,421,772
Derivative assets	16,012	15,579
Total recurring fair value measurements-assets	1,678,422	1,437,351
Derivative liabilities	16,440	15,006
Total recurring fair value measurements-liabilities	16,440	15,006
Municipal obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	18,767	35,961
U.S. Treasury and government agency securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	300,702	505
Corporate debt securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	3,500	3,500
Mortgage-backed securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	1,241,223	1,276,958
Collateralized mortgage obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	88,558	94,125
Equity securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	9,660	10,723
Level 1 [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	313,862	14,728
Derivative assets	'	'
Total recurring fair value measurements-assets	313,862	14,728
Derivative liabilities	'	'
Total recurring fair value measurements-liabilities	'	'
Level 1 [Member] | Municipal obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'
Level 1 [Member] | U.S. Treasury and government agency securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	300,702	505
Level 1 [Member] | Corporate debt securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	3,500	3,500
Level 1 [Member] | Mortgage-backed securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'
Level 1 [Member] | Collateralized mortgage obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'
Level 1 [Member] | Equity securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	9,660	10,723
Level 2 [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	1,348,548	1,407,044
Derivative assets	16,012	15,579
Total recurring fair value measurements-assets	1,364,560	1,422,623
Derivative liabilities	16,440	15,006
Total recurring fair value measurements-liabilities	16,440	15,006
Level 2 [Member] | Municipal obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	18,767	35,961
Level 2 [Member] | U.S. Treasury and government agency securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'
Level 2 [Member] | Corporate debt securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'
Level 2 [Member] | Mortgage-backed securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	1,241,223	1,276,958
Level 2 [Member] | Collateralized mortgage obligations [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	88,558	94,125
Level 2 [Member] | Equity securities [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'	'
Available for sale debt securities	'	'

Fair_Value_Additional_Informat

Fair Value - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Loans held for sale	'90 days
Minimum [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Period of Investment	'2 years
Maximum [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Period of Investment	'5 years

Fair_Value_Schedule_of_Financi1

Fair Value - Schedule of Financial Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Collateral-dependent impaired loans	$34,482	$24,392
Other real estate owned	20,742	25,525
Total nonrecurring fair value measurements	55,224	49,917
Level 1 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Collateral-dependent impaired loans	'	'
Other real estate owned	'	'
Total nonrecurring fair value measurements	'	'
Level 2 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Collateral-dependent impaired loans	34,482	24,392
Other real estate owned	'	'
Total nonrecurring fair value measurements	34,482	24,392
Level 3 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Collateral-dependent impaired loans	'	'
Other real estate owned	20,742	25,525
Total nonrecurring fair value measurements	$20,742	$25,525

Fair_Value_Schedule_of_Estimat

Fair Value - Schedule of Estimated Fair Values of Financial Instruments (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Available for sale securities	$1,662,410	$1,421,772
Held to maturity securities	2,250,960	2,611,352
Loans, net	13,223,002	12,191,191
Loans held for sale	15,098	24,515
Derivative financial instruments	16,012	15,579
Deposits	15,736,694	15,360,516
Long-term debt	376,452	385,826
Derivative financial instruments	16,440	15,006
Level 1 [Member]	'	'
Cash, interest-bearing bank deposits, and federal funds sold	803,917	617,280
Available for sale securities	313,862	14,728
Held to maturity securities	'	100,316
Loans, net	'	'
Loans held for sale	'	'
Accrued interest receivable	44,164	42,977
Derivative financial instruments	'	'
Deposits	'	'
Federal funds purchased	7,625	7,725
Securities sold under agreements to repurchase	599,184	650,235
FHLB borrowings	565,000	'
Long-term debt	'	'
Accrued interest payable	5,663	4,353
Derivative financial instruments	'	'
Level 2 [Member]	'	'
Cash, interest-bearing bank deposits, and federal funds sold	'	'
Available for sale securities	1,348,548	1,407,044
Held to maturity securities	2,253,219	2,476,268
Loans, net	34,482	24,392
Loans held for sale	15,098	24,515
Accrued interest receivable	'	'
Derivative financial instruments	16,012	15,579
Deposits	'	'
Federal funds purchased	'	'
Securities sold under agreements to repurchase	'	'
FHLB borrowings	'	'
Long-term debt	344,636	385,557
Accrued interest payable	'	'
Derivative financial instruments	16,440	15,006
Level 3 [Member]	'	'
Cash, interest-bearing bank deposits, and federal funds sold	'	'
Available for sale securities	'	'
Held to maturity securities	'	'
Loans, net	13,081,700	12,023,330
Loans held for sale	'	'
Accrued interest receivable	'	'
Derivative financial instruments	'	'
Deposits	15,434,876	15,352,024
Federal funds purchased	'	'
Securities sold under agreements to repurchase	'	'
FHLB borrowings	'	'
Long-term debt	'	'
Accrued interest payable	'	'
Derivative financial instruments	'	'
Total Fair Value [Member]	'	'
Cash, interest-bearing bank deposits, and federal funds sold	803,917	617,280
Available for sale securities	1,662,410	1,421,772
Held to maturity securities	2,253,219	2,576,584
Loans, net	13,116,182	12,047,722
Loans held for sale	15,098	24,515
Accrued interest receivable	44,164	42,977
Derivative financial instruments	16,012	15,579
Deposits	15,434,876	15,352,024
Federal funds purchased	7,625	7,725
Securities sold under agreements to repurchase	599,184	650,235
FHLB borrowings	565,000	'
Long-term debt	344,636	385,557
Accrued interest payable	5,663	4,353
Derivative financial instruments	16,440	15,006
Carrying Amount [Member]	'	'
Cash, interest-bearing bank deposits, and federal funds sold	803,917	617,280
Available for sale securities	1,662,410	1,421,772
Held to maturity securities	2,250,960	2,611,352
Loans, net	13,223,002	12,191,191
Loans held for sale	15,098	24,515
Accrued interest receivable	44,164	42,977
Derivative financial instruments	16,012	15,579
Deposits	15,736,694	15,360,516
Federal funds purchased	7,625	7,725
Securities sold under agreements to repurchase	599,184	650,235
FHLB borrowings	565,000	'
Long-term debt	376,452	385,826
Accrued interest payable	5,663	4,353
Derivative financial instruments	$16,440	$15,006

Derivatives_Fair_Values_of_Der

Derivatives - Fair Values of Derivative Instruments on Balance Sheet (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Derivative Fair Value Of Asset	$16,012	$15,579
Derivative Fair Value Of Liability	16,440	15,006
Derivatives not designated as hedging instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	940,396	763,568
Derivative Fair Value Of Asset	16,012	15,579
Derivative Fair Value Of Liability	16,440	15,006
Derivatives not designated as hedging instruments [Member] | Interest rate swaps [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	753,382	650,667
Derivative Fair Value Of Asset	14,585	14,147
Derivative Fair Value Of Liability	14,974	13,777
Derivatives not designated as hedging instruments [Member] | Risk participation agreements [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	80,989	19,736
Derivative Fair Value Of Asset	105	2
Derivative Fair Value Of Liability	156	2
Derivatives not designated as hedging instruments [Member] | Forward commitments to sell residential mortgage loans [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	40,873	45,910
Derivative Fair Value Of Asset	56	326
Derivative Fair Value Of Liability	640	115
Derivatives not designated as hedging instruments [Member] | Interest rate-lock commitments on residential mortgage loans [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	28,025	25,956
Derivative Fair Value Of Asset	595	56
Derivative Fair Value Of Liability	27	107
Derivatives not designated as hedging instruments [Member] | Foreign exchange forward contracts [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Notional Amount	37,127	21,299
Derivative Fair Value Of Asset	671	1,048
Derivative Fair Value Of Liability	$643	$1,005

Derivatives_Additional_Informa

Derivatives - Additional Information (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Termination value of derivatives in a net liability position	$6
Collateral obligations for derivative counterparties	$17

Derivatives_Offsetting_Derivat

Derivatives - Offsetting Derivative Assets and Liabilities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'
Gross Amounts Recognized	$15,129	$13,779
Gross Amounts Offset in the Statement of Financial Position	'	'
Net Amounts Presented in the Statement of Financial Position	15,129	13,779
Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	2,206	3,462
Gross Amounts Not offset in the Statement of Financial Position -Cash Collateral	16,767	7,406
Net Amount	-3,844	2,911
Gross Amounts Recognized	14,690	14,149
Gross Amounts Offset in the Statement of Financial Position	'	'
Net Amounts Presented in the Statement of Financial Position	14,690	14,149
Gross Amounts Not Offset in the Statement of Financial Position - Financial Instruments	2,206	3,462
Gross Amounts Not offset in the Statement of Financial Position -Cash Collateral	'	'
Net Amount	$12,484	$10,687

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 16, 2014	5-May-14	8-May-13	Apr. 30, 2013
Stockholders' Equity Note [Abstract]	'	'	'	'
Shares authorized for repurchase	5.00%	'	'	5.00%
Shares authorized for repurchase	4,000,000	'	'	'
Repurchased common stock shares	305,263	600,000	3,000,000	'
Repurchase of common stock per share	$32.65	'	'	'
Accelerated share repurchase transaction, paid	'	'	$115	'
Percentage of repurchased accelerated share repurchase program	'	'	76.00%	'

Stockholders_Equity_Components

Stockholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Accumulated other comprehensive income (loss), Beginning balance	'	'	($35,379)	($22,925)
Net change in unrealized (losses) gains	-6,293	-9,685	9,119	-96,074
Reclassification of net losses realized and included in earnings	'	'	2,195	5,835
Amortization of unrealized net gain (loss) on securities transferred to held to maturity	892	-1,456	2,463	-7,099
Income tax (benefit) expense	'	'	5,091	-35,492
Accumulated other comprehensive income (loss), Ending balance	-26,693	-84,771	-26,693	-84,771
Available for Sale Securities [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Accumulated other comprehensive income (loss), Beginning balance	'	'	8,263	38,854
Net change in unrealized (losses) gains	'	'	9,119	-96,070
Transfer of net unrealized gain from AFS to HTM, net of cumulative tax effect	'	'	'	36,208
Income tax (benefit) expense	'	'	3,309	-35,115
Accumulated other comprehensive income (loss), Ending balance	14,073	14,107	14,073	14,107
Held to Maturity Securities Transferred from AFS [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Accumulated other comprehensive income (loss), Beginning balance	'	'	-21,189	19,090
Transfer of net unrealized gain from AFS to HTM, net of cumulative tax effect	'	'	'	-36,208
Amortization of unrealized net gain (loss) on securities transferred to held to maturity	'	'	2,463	-7,099
Income tax (benefit) expense	'	'	879	-2,563
Accumulated other comprehensive income (loss), Ending balance	-19,605	-21,654	-19,605	-21,654
Employee Benefit Plans [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Accumulated other comprehensive income (loss), Beginning balance	'	'	-22,453	-80,688
Reclassification of net losses realized and included in earnings	'	'	2,195	5,534
Income tax (benefit) expense	'	'	903	2,070
Accumulated other comprehensive income (loss), Ending balance	-21,161	-77,224	-21,161	-77,224
Loss on Effective Cash Flow Hedges [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Accumulated other comprehensive income (loss), Beginning balance	'	'	'	-181
Net change in unrealized (losses) gains	'	'	'	-4
Reclassification of net losses realized and included in earnings	'	'	'	301
Income tax (benefit) expense	'	'	'	$116

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Line Item Affected by Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Comprehensive Income Loss Amount Reclassified From Accumulated Other Comprehensive Income [Abstract]	'	'	'	'
Amortization/accretion of unrealized net gain/(loss) on securities transferred to HTM	$892	($1,456)	$2,463	($7,099)
Tax effect	'	'	879	-2,563
Net of tax	'	'	1,584	-4,536
Amortization of defined benefit pension and post-retirement items	'	'	293	5,534
Tax effect	'	'	103	2,070
Net of tax	'	'	190	3,464
Gains and losses on cash flow hedges	'	'	'	301
Tax effect	'	'	'	105
Net of tax	'	'	'	196
Total reclassifications, net of tax	'	'	$1,774	($876)

Earnings_Per_Share_Computation

Earnings Per Share - Computation of Earnings Per Common Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'	'	'
Net income to common shareholders	$46,553	$33,202	$135,630	$128,640
Net income allocated to participating securities - basic and diluted	883	616	2,783	2,398
Net income allocated to common shareholders - basic and diluted	$45,670	$32,586	$132,847	$126,242
Denominator:	'	'	'	'
Weighted average common shares - basic	81,721	82,091	81,965	83,404
Dilutive potential common shares	221	114	239	92
Weighted average common shares - diluted	81,942	82,205	82,204	83,496
Earnings per common share:	'	'	'	'
Basic	$0.56	$0.40	$1.62	$1.51
Diluted	$0.56	$0.40	$1.62	$1.51

Earnings_Per_Share_Additional_

Earnings Per Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Weighted-average anti-dilutive potential common shares	569,404	721,863	639,486	1,076,894

ShareBased_Payment_Arrangement2

Share-Based Payment Arrangements - Schedule of Option Activity Under Stock Option Plans (Detail) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Number of Shares, Outstanding at Beginning	1,332,656
Number of Shares, Exercised	-32,618
Number of Shares, Forfeited	-16,549
Number of Shares, Expired	-113,447
Number of Shares, Outstanding at Ending	1,170,042
Number of Shares, Exercisable at Ending	885,673
Weighted- Average Exercise Price, Outstanding at Beginning	$38.85
Weighted- Average Exercise Price, Exercised	$29.51
Weighted- Average Exercise Price, Forfeited	$38.26
Weighted- Average Exercise Price, Expired	$63.41
Weighted- Average Exercise Price, Outstanding at Ending	$36.74
Weighted- Average Exercise Price, Exercisable at Ending	$38.55
Weighted-Average Remaining Contractual Term, Outstanding at Ending Balance (in years)	'4 years 4 months 24 days
Weighted-Average Remaining Contractual Term, Exercisable at Ending Balance (in years)	'3 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding at Ending	$799
Aggregate Intrinsic Value, Exercisable at Ending	$373

ShareBased_Payment_Arrangement3

Share-Based Payment Arrangements - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
	Bank
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Intrinsic value of options exercised	$0.20	$0.10
Unrecognized compensation cost	31.7	'
Weighted-average period in years	'3 years 1 month 6 days	'
Total fair value of shares vested	$10	$1
Shareholder return period	'3 years	'
Number of peer group of regional banks	50	'
Performance Share Award [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares granted to key members of executives and senior management	69,857	'
Weighted average fair value of shares granted	$38.14	'
Percentage of maximum number of shares earned of target award	200.00%	'

ShareBased_Payment_Arrangement4

Share-Based Payment Arrangements - Schedule of Nonvested Restricted and Performance Shares (Detail) (Restricted Stock and Performance Shares [Member], USD $)	9 Months Ended
	Sep. 30, 2014
Restricted Stock and Performance Shares [Member]	'
Nonvested Share Activity [Line Items]	'
Number of Shares, Nonvested at Beginning	1,981,820
Number of Shares, Granted	120,396
Number of Shares, Vested	-272,788
Number of Shares, Forfeited	-85,873
Number of Shares, Nonvested at Ending	1,743,555
Weighted-Average Grant-Date Fair Value, Nonvested at Beginning	$31.75
Weighted-Average Grant-Date Fair Value, Granted	$36.23
Weighted-Average Grant-Date Fair Value, Vested	$32
Weighted-Average Grant-Date Fair Value, Forfeited	$31.69
Weighted-Average Grant-Date Fair Value, Nonvested at Ending	$32.02

Retirement_Plans_Components_of

Retirement Plans - Components of Net Periodic Benefits Cost (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits [Member]	'	'	'	'
Defined Benefit Plan Net Periodic Benefit Cost [Line Items]	'	'	'	'
Service cost	$3,230	$3,969	$9,690	$11,905
Interest cost	4,812	4,151	14,438	12,457
Expected return on plan assets	-8,056	-6,982	-24,167	-20,946
Amortization of net loss	7	1,605	20	4,813
Net periodic benefit cost	-7	2,743	-19	8,229
Other Post-retirement Benefits [Member]	'	'	'	'
Defined Benefit Plan Net Periodic Benefit Cost [Line Items]	'	'	'	'
Service cost	31	52	94	162
Interest cost	285	327	855	987
Expected return on plan assets	'	'	'	'
Amortization of net loss	91	459	273	1,320
Net periodic benefit cost	$407	$838	$1,222	$2,469

Retirement_Plans_Additional_In

Retirement Plans - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Percentage of compensation saved by participant for which employer contributes hundred percent	100.00%
Employer matching contribution for first one percent of compensation saved	1.00%
Percentage of compensation saved by participant for which employer contributes fifty percent	50.00%
Employer matching contribution for next five percent of compensation saved	5.00%

Other_Noninterest_Income_Compo

Other Noninterest Income - Components of Other Noninterest Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]	'	'	'	'
Income from bank owned life insurance	$2,377	$2,656	$7,048	$8,764
Credit related fees	2,822	2,995	8,388	5,969
Income from derivatives	191	1,257	1,431	3,296
Net(loss) gain on sale of assets	-56	801	1,409	1,277
Safety deposit box income	448	467	1,404	1,480
Other miscellaneous	1,950	1,940	7,091	6,453
Total other noninterest income	$7,732	$10,116	$26,771	$27,239

Other_Noninterest_Expense_Comp

Other Noninterest Expense - Components of Other Noninterest Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]	'	'	'	'
Advertising	$2,457	$2,858	$6,395	$7,216
Ad valorem and franchise taxes	3,098	2,809	8,397	7,193
Printing and supplies	1,189	1,143	3,467	3,963
Insurance expense	944	887	3,002	3,018
Travel expense	1,009	1,074	2,966	3,475
Entertainment and contributions	1,396	969	4,337	3,960
Tax credit investment amortization	2,220	4,880	6,590	7,553
Other miscellaneous	6,821	19,851	25,105	32,504
Total other noninterest expense	$19,134	$34,471	$60,259	$68,882

Other_Noninterest_Expense_Addi

Other Noninterest Expense - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Nonoperating expense [Line Items]	'	'	'	'	'
Other miscellaneous expenses	$6,821,000	'	$19,851,000	$25,105,000	$32,504,000
Expense related to the settlement of the assessment with the FDIC	'	10,300,000	'	'	'
Gain on Sale of Insurance Business	'	'	'	9,400,000	'
Sales price of divested business	'	'	'	15,500,000	'
Early termination fee of reverse repurchase obligations	'	3,500,000	'	'	'
Other Miscellaneous Expense [Member]	'	'	'	'	'
Nonoperating expense [Line Items]	'	'	'	'	'
Other miscellaneous expenses	1,100,000	7,300,000	12,600,000	'	'
Branch Closures [Member]	'	'	'	'	'
Nonoperating expense [Line Items]	'	'	'	'	'
Expense related to closure of branches	1,100,000	3,500,000	'	'	'
Number of branch locations	'	15	'	'	'
Branch Closures [Member] | Other Miscellaneous Expense [Member]	'	'	'	'	'
Nonoperating expense [Line Items]	'	'	'	'	'
Expense related to closure of branches	'	$2,900,000	'	'	'